Geometrical isomerization of arachidonic acid during lipid peroxidation interferes with ferroptosis

Study on the mechanism of Huangqi Chifeng decoction regulating ferroptosis inhibiting smooth muscle cells derived foam cell formation

ETHNOPHARMACOLOGICAL RELEVANCE

Chinese medicine, specifically Huangqi Chifeng Decoction (HQCF), is recognized for its efficacy in treating atherosclerosis (AS), a common cardiovascular disease. Despite its established benefits in addressing Qi deficiency, blood stasis, and collateral obstruction, the precise mechanism through which HQCF affects AS remains unclear.

AIM OF THE STUDY

This study investigated the potential of HQCF to mitigate AS by suppressing smooth muscle cell (SMC) foam formation through the ferroptosis pathway.

MATERIALS AND METHODS

An AS model was established using ApoE-/- mice fed a high-fat diet (HFD), and the role of HQCF in regulating ferroptosis in AS was examined. Using a single-cell proteomics analysis strategy, we identified the primary targets of HQCF in SMCs. Additionally, an oxidized low-density lipoprotein (ox-LDL)-treated SMC-derived foam cell model was established. The effects HQCF on SMC ferroptosis were analyzed, and ox-LDL-induced SMCs were pretreated with small interfering RNA (siRNA) and overexpressing carrier plasmids (pcDNA) to identify potential therapeutic targets, for specifically thioredoxin (TXN).

RESULTS

HQCF the pathological state of the aorta in ApoE-/- mice, regulated lipid levels, improved antioxidant capacity, modulated the phenotypic transformation of SMCs, and maintained the dynamic balance of extracellular matrix degradation and remodeling. Additionally, HQCF may inhibit ferroptosis via positive regulation of the GPX4/xCT signaling pathway. Single-cell proteomics revealed 36 common differentially expressed proteins (DEPs), suggesting that HQCF's treatment of AS may be associated with the regulation of cellular function and redox homeostasis. The abnormal expression of TXN in SMCs may be related to the phenotypic transition induced by AS. HQCF was also found to ameliorate oxidative stress and mitochondrial dysfunction during SMC foaming. Moreover, ferroptosis was involved in ox-LDL-induced foam cell formation, and HQCF alleviated these pathologies by inhibiting ferroptosis. The protective effect of HQCF on SMCs was enhanced by TXN overexpression but partially reversed by TXN knockdown, further indicating that HQCF's regulation of SMC function and inhibition of ferroptosis is, at least in part, mediated by TXN.

CONCLUSION

These findings suggest that HQCF protects SMCs from ferroptosis by regulating the TXN/xCT/GPX4 pathway, ameliorating the aortic pathological state, alleviating oxidative stress, and maintaining mitochondrial homeostasis in mice.

Activation of gut metabolite ACSL4/LPCAT3 by microplastics in drinking water mediates ferroptosis via gut-kidney axis

The environmental pollutant Benzo[a]pyrene (BaP) is commonly found in the environment, with microplastics (MPs) acting as the primary carriers of BaP into living organisms, increasing its availability in the body. However, the specific pathways and mechanisms through which MPs carrying pollutants cause kidney damage are not fully understood. This study aimed to investigate the routes and mechanisms of kidney injury in mice to low concentrations of both MPs and BaP. The combination of polystyrene (PS) and BaP disrupted lipid metabolism in the kidneys, leading to a form of cell death known as ferroptosis. However, this effect was not observed in HK-2 cells in vitro, indicating a cell-specific response. Interestingly, in HIEC-6 cells, both PS and BaP directly induced ferroptosis. These findings confirm that exposure to both PS and BaP can disrupt metabolic homeostasis in the kidneys, contributing to kidney dysfunction and cell death.

18beta-glycyrrhetinic acid alleviates deoxynivalenol-induced hepatotoxicity by inhibiting GPX4-dependent ferroptosis

Deoxynivalenol (DON), a mycotoxin that severely contaminates agri-food products can cause hepatotoxicity. Ferroptosis is an iron-dependent form of cell death, and the liver is an important organ for iron accumulation. 18beta-glycyrrhetinic acid (GA) has anti-ferroptosis and hepatoprotective effects. This study aimed to investigate the role of ferroptosis in the protective effects of GA against DON-induced hepatotoxicity in HepG2 cells and mice. The in vitro results revealed that DON (0.4 μM) decreased GPX4, SLC7A11, GCLC, NQO1, and Nrf2 expression; promoted TFR-1 expression and MDA, 4-HNE, and total ROS production; accelerated GSH depletion; and enhanced lipid ROS accumulation and Fe(II) overload, leading to ferroptosis. Pre-treatment with GA (0.4 and 6 μM) reversed these changes and alleviated DON-induced ferroptosis, thereby increasing cell viability and proliferation. In vivo results also showed that GA (10 mg/kg bw) pre-administration attenuated DON (2 mg/kg bw)-induced mouse liver injury, in part by inhibiting ferroptosis through reducing mitochondrial damage and lipid peroxidation. In addition, GA prevented erastin- and RSL3-induced ferroptosis by promoting GPX4 and SLC7A11 expression. Altogether, GA attenuated DON-induced hepatotoxicity by preventing ferroptosis via activation of GPX4-dependent pathway. The findings of this study provide a theoretical basis for the prevention of food mycotoxin toxicity.

Conjugated fatty acids drive ferroptosis through chaperone-mediated autophagic degradation of GPX4 by targeting mitochondria

Conjugated fatty acids (CFAs) have been known for their anti-tumor activity. However, the mechanism of action remains unclear. Here, we identify CFAs as inducers of glutathione peroxidase 4 (GPX4) degradation through chaperone-mediated autophagy (CMA). CFAs, such as (10E,12Z)-octadecadienoic acid and α-eleostearic acid (ESA), induced GPX4 degradation, generation of mitochondrial reactive oxygen species (ROS) and lipid peroxides, and ultimately ferroptosis in cancer cell lines, including HT1080 and A549 cells, which were suppressed by either pharmacological blockade of CMA or genetic deletion of LAMP2A, a crucial molecule for CMA. Mitochondrial ROS were sufficient and necessary for CMA-dependent GPX4 degradation. Oral administration of an ESA-rich oil attenuated xenograft tumor growth of wild-type, but not that of LAMP2A-deficient HT1080 cells, accompanied by increased lipid peroxidation, GPX4 degradation and cell death. Our study establishes mitochondria as the key target of CFAs to trigger lipid peroxidation and GPX4 degradation, providing insight into ferroptosis-based cancer therapy.

The Role of Fatty Acid Metabolism, the Related Potential Biomarkers, and Targeted Therapeutic Strategies in Gastrointestinal Cancers

Gastrointestinal cancer has emerged as a significant global health concern due to its high incidence and mortality, limited effectiveness of early detection, suboptimal treatment outcomes, and poor prognosis. Metabolic reprogramming is a prominent feature of cancer, and fatty acid metabolism assumes a pivotal role in bridging glucose metabolism and lipid metabolism. Fatty acids play important roles in cellular structural composition, energy supply, signal transduction, and other lipid-related processes. Changes in the levels of fatty acid metabolite may indicate the malignant transformation of gastrointestinal cells, which have an impact on the prognosis of patients and can be used as a marker to monitor the efficacy of anticancer therapy. Therefore, targeting key enzymes involved in fatty acid metabolism, either as monotherapy or in combination with other agents, is a promising strategy for anticancer treatment. This article reviews the potential mechanisms of fatty acid metabolism disorders in the occurrence and development of gastrointestinal tumors, and summarizes the related potential biomarkers and anticancer strategies.

Roquin-2 promotes oxidative stress-induced cell death by ubiquitination-dependent degradation of TAK1

Reactive oxygen species (ROS) are highly reactive and their accumulation causes oxidative damage to cells. Cells maintain survival upon mild oxidative stress with anti-oxidative systems, such as the kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) system. On the other hand, upon severe oxidative stress, cells undergo regulated cell death, including apoptosis, for eliminating damaged cells. To execute efficient cell death, cells need to turn off the anti-oxidant systems, while triggering cell death. However, it remains unknown how cells orchestrate these two conflicting systems under excessive oxidative stress. Herein, we show that when cells are exposed to excessive oxidative damage, an E3 ubiquitin ligase Roquin-2 (also known as RC3H2) plays a key role in switching cell fate from survival to death by terminating activation of transforming growth factor-β-activated kinase 1 (TAK1), a positive regulator for Nrf2 activation. Roquin-2 interacted with TAK1 via four cysteine residues in TAK1 (C96, C302, C486, and C500) that are susceptible to oxidative stress and participate in oligomer formation via disulfide bonds, promoting K48-linked polyubiquitination and degradation of TAK1. Nrf2 was inactivated upon lethal oxidative stress in wild-type mouse embryonic fibroblast (MEF) cells, whereas it sustained activation and conferred resistance to Roquin-2 deficient cells, which was reversed by pharmacological or genetic inhibition of TAK1. These data demonstrate that in response to excessive ROS exposure, Roquin-2 promotes ubiquitination and degradation of TAK1 to suppress Nrf2 activation, and thereby contributes to an efficient cell death, providing insight into the pathogenesis of oxidative stress-related diseases, including cancer.

Ferroptosis: a new mechanism of traditional Chinese medicine for treating ulcerative colitis

Ulcerative colitis (UC), a subtype of inflammatory bowel disease, manifests with symptoms such as abdominal pain, diarrhea, and mucopurulent, bloody stools. The pathogenesis of UC is not fully understood. At present, the incidence of UC has increased significantly around the world. Conventional therapeutic arsenals are relatively limited, with often poor efficacy and many adverse effects. In contrast, traditional Chinese medicine (TCM) holds promise due to their notable effectiveness, reduced recurrence rates, and minimal side effects. In recent years, significant progress has been made in the basic research on TCM for UC treatment. It has been found that the inhibition of ferroptosis through the intervention of TCM can significantly promote intestinal mucosal healing and reverse UC. The mechanism of action involves multiple targets and pathways.

Aim of the review

This review summarizes the experimental studies on the targeted regulation of ferroptosis by TCM and its impact on UC in recent years, aiming to provide theoretical basis for the prevention, treatment, and further drug development for UC.

Results

Ferroptosis disrupts antioxidant mechanisms in intestinal epithelial cells, damages the intestinal mucosa, and participates in the pathological process of UC. TCM acts on various pathways such as Nrf2/HO-1 and GSH/GPX4, blocking the pathological progression of ferroptosis in intestinal epithelial cells, inhibiting pathological damage to the intestinal mucosa, and thereby alleviating UC.

Conclusion

The diverse array of TCM single herbs, extracts and herbal formulas facilitates selective and innovative research and development of new TCM methods for targeting UC treatment. Although progress has been made in studying TCM compound formulas, single herbs, and extracts, there are still many issues in clinical and basic experimental designs, necessitating further in-depth scientific exploration and research.

Evaluating the efficacy and mechanisms of Hua-Zhuo-Ning-Fu-Decoction on psoriasis using integrated bioinformatics analysis and metabolomics

ETHNOPHARMACOLOGICAL RELEVANCE

Hua Zhuo Ning Fu Decoction (HZD) is an empirical prescription from traditional Chinese medicine that shows excellent clinical results for psoriasis patients. Uncertainty lingered over HZD's potential anti-psoriasis mechanisms.

AIM OF THE STUDY

The study's objective is to investigate the pharmacological processes and therapeutic effects of HZD on psoriasis.

MATERIALS AND METHODS

In the initial phase of the study, an investigation was conducted to assess the effects of HZD on psoriasis-afflicted mice using an imiquimod (IMQ)-induced murine model. The experimental mice were randomly allocated to different groups, including the IMQ-induced model group, the control group, the HZD therapy groups with varying dosage levels (low, medium, and high), and Dexamethasone (DEX, the positive control medicine) group. Bioinformatics analysis and molecular docking were subsequently employed to identify the primary components and molecular targets associated with the therapeutic action of HZD in the context of psoriasis. Additionally, to find the impacts on metabolite regulation, plasma metabolomics based on ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) was used. It's interesting to note that the combined mechanisms from metabolomics were examined in tandem with the targets. In vivo tests were the last step in validating the potential mechanism. Throughout the trial, the following data were recorded: body weight, psoriasis area and severity index (PASI). The molecular targets connected to HZD's anti-psoriasis activities were revealed using histological examination, western blot (WB), and ELISA investigation.

RESULTS

In mice induced with IMQ, HZD shown good anti-psoriasis effects in terms of PASI score and epidermal acanthosis. 95 HZD targets and 77 bioactive chemicals connected to psoriasis were found by bioinformatics research; of these, 7 key targets (EPHX2, PLA2G2A, TBXAS1, MAOA, ALDH1A3, ADH1A, and ADH1B) were linked to the mechanisms of HZD, the combination degree of which was finally expressed by the score of docking. In addition, HZD regulated nine metabolites. In line with this, HZD modified three metabolic pathways. Additionally, a combined examination of 7 key targets and 9 metabolites suggested that the metabolism of arachidonic acid might be the key metabolic route, which was identified by ELISA analysis. The in vivo investigation shown that HZD could control cytokines associated to inflammation (IL-10, TGF-β, IL-17A, and IL-23), as well as important antioxidant system markers (ROS, GSH, and MDA). Moreover, HZD controlled iron levels and the expression of ferroptosis-related proteins (ACSL4 and GPX4), suggesting that ferroptosis played a crucial role in this process.

CONCLUSIONS

Our findings demonstrated the whole mechanism and anti-psoriasis effectiveness of HZD, which will promote its clinical application and aid in the investigation of new bioactive components of HZD against psoriasis.

Biomarkers of Oxidative and Radical Stress

Reactive oxygen and nitrogen species (ROS/RNS) are generated as a result of normal intracellular metabolism [...].

Lipid Peroxidation and Antioxidant Protection

Lipid peroxidation (LP) is the most important type of oxidative-radical damage in biological systems, owing to its interplay with ferroptosis and to its role in secondary damage to other biomolecules, such as proteins. The chemistry of LP and its biological consequences are reviewed with focus on the kinetics of the various processes, which helps understand the mechanisms and efficacy of antioxidant strategies. The main types of antioxidants are discussed in terms of structure-activity rationalization, with focus on mechanism and kinetics, as well as on their potential role in modulating ferroptosis. Phenols, pyri(mi)dinols, antioxidants based on heavy chalcogens (Se and Te), diarylamines, ascorbate and others are addressed, along with the latest unconventional antioxidant strategies based on the double-sided role of the superoxide/hydroperoxyl radical system.