Geometrical isomerization of arachidonic acid during lipid peroxidation interferes with ferroptosis

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.