4-octyl itaconate protects against oxidative stress-induced liver injury by activating the Nrf2/Sirt3 pathway through AKT and ERK1/2 phosphorylation

Preclinical insights into the potential of itaconate and its derivatives for liver disease therapy

Annually, approximately 3.5 % of the world's population dies of cirrhosis or liver cancer, and the burden of liver disease is steadily expanding owing to multiple factors such as alcohol consumption, irrational diets, viral transmission, and exposure to drugs and toxins. However, the lack of effective therapies and the adverse effects of some medications remain a threat to the management of liver disease. Recently, immunometabolism, as an emerging discipline, appears to be the focus of unprecedented research. As a natural metabolite that regulates cellular functions, itaconate is a crucial bridge connecting metabolism and immune response. Remodeling immune function through metabolic modulation may be a promising alternative for disease intervention strategies. In this review, we first briefly describe the historical origin of itaconate and the development of its derivatives. This was followed by a review of the molecular mechanisms by which itaconate regulated immune-metabolic responses. Furthermore, we analyzed the effects of itaconate regulation on immune cells of the hepatic system. Finally, we summarized the experimental evidence for itaconate and its derivatives in the therapeutic application of liver diseases. Itaconate is potentially an invaluable component of emerging therapeutic strategies for liver disease.

Oxymatrine alleviates ALD-induced cardiac hypertrophy by regulating autophagy via activation Nrf2/SIRT3 signaling pathway

BACKGROUND

Cardiac hypertrophy is a prevalent early pathological manifestation in various cardiovascular diseases, lacking effective interventions to impede its progression. Although oxymatrine (OMT) has shown potential benefits for cardiac function, its therapeutic efficacy and mechanism in cardiac hypertrophy remain incompletely understood. Notably, mitochondrial damage and dysregulated autophagy are pivotal pathogenic mechanisms in cardiac hypertrophy.

PURPOSE

We investigate the pharmacological characteristics and mechanism of OMT in mitochondrial function and autophagy in cardiac hypertrophy.

STUDY DESIGN AND METHODS

A murine model of cardiac hypertrophy was induced by aldosterone in combination with high-salt drinking water, while primary cardiomyocyte hypertrophy was induced by aldosterone in vitro. Cardiac hypertrophy was assessed using echocardiography and histopathological staining. Autophagosomes and mitochondrial morphology were visualized by transmission electron microscopy. Levels of reactive oxygen species (ROS), malondialdehyde (MDA), and adenosine triphosphate (ATP) were quantified using commercial kits. The binding affinity of OMT with Nrf2 was assessed through molecular docking. Furthermore, adenovirus, agonists, and inhibitors were employed to modulate Nrf2, followed by quantitative real-time polymerase chain reaction (qRT-PCR), immunoblotting, co-immunoprecipitation, chromatin immunoprecipitation, immunohistochemistry, and cellular thermal shift assay.

RESULTS

OMT effectively attenuated aldosterone-induced cardiac hypertrophy both in vivo and in vitro. OMT promoted the activation of Nrf2, leading to elevated SIRT3 expression and enhanced autophagolysosome fusion, thereby modulating mitophagy and improving mitochondrial function. Moreover, the cardioprotective effects of OMT were abolished upon silencing or inhibition of Nrf2. OMT binds to Nrf2, facilitating its dissociation and nuclear translocation.

CONCLUSION

OMT activates Nrf2, consequently enhancing SIRT3 transcription, restoring autophagic flux, and preserving mitochondrial integrity, thereby mitigating aldosterone-induced cardiac hypertrophy. In summary, our study is the first to discover and confirm that OMT can stabilize Nrf2, promoting its activation and subsequently up-regulating SIRT3, which in turn facilitates mitochondrial autophagy. Additionally, PARKIN appears to play a key role in SIRT3-mediated regulation of mitophagy, warranting further investigation.

4-Octyl Itaconate Alleviates Myocardial Ischemia-Reperfusion Injury Through Promoting Angiogenesis via ERK Signaling Activation

Myocardial ischemia-reperfusion (IR) injury is a critical complication following revascularization therapy for ischemic heart disease. Itaconate, a macrophage-derived metabolite, has been implicated in inflammation and metabolic regulation. This study investigates the protective role of itaconate derivatives against IR injury. Using a mice model of IR injury, the impact of 7-day 4-Octyl itaconate (4-OI) administration on cardiac function is assessed. Exogenous administration of 4-OI significantly reduces myocardial damage, enhances angiogenesis, and alleviates myocardial hypoxia injury during reperfusion. RNA sequencing and molecular docking techniques are used to find the target of itaconate, and changes in cardiac function are observed in Immune-Responsive Gene1 (IRG1) global knockout mice. In cell culture studies, 4-OI promotes endothelial cell proliferation and migration, mediated by Mitogen-Activated Protein Kinases (MAPK) signaling pathway activation, particularly through Extracellular Signal-Regulated Kinase (ERK) signaling. Inhibition of ERK blocks these beneficial effects on endothelial cells. Furthermore, itaconate synthesis inhibition worsens myocardial damage, which is mitigated by 4-OI supplementation. The results indicate that 4-OI promotes angiogenesis by activating MAPK signaling via FMS-like tyrosine kinase 1 (Flt1), highlighting its potential as a therapeutic strategy for myocardial IR injury.

Activation of Nrf2 pathway by 4-Octyl itaconate enhances donor lung function in cold preservation settings

BACKGROUND

Lung transplantation is the primary treatment for end-stage lung diseases. However, ischemia-reperfusion injury (IRI) significantly impacts transplant outcomes. 4-Octyl itaconate (4-OI) has shown potential in mitigating organ IRI, although its effects in lung transplantation require further exploration.

METHODS

BEAS-2B cells were used to model transplantation, assessing the effects of 4-OI through viability, apoptosis, and ROS assays. qRT-PCR analyzed cytokine transcription post-cold ischemia/reperfusion (CI/R). RNA sequencing and Gene Ontology analysis elucidated 4-OI's mechanisms of action, confirmed by Western blotting. ALI-airway and lung transplantation organoid models evaluated improvements in bronchial epithelial morphology and function due to 4-OI. ELISA measured IL-6 and IL-8 levels. Rat models of extended cold preservation and non-heart-beating transplantation assessed 4-OI's impact on lung function, injury, and inflammation.

RESULTS

Our findings indicate that 4-OI (100 µM) during cold preservation effectively maintained cell viability, decreased apoptosis, and reduced ROS production in BEAS-2B cells under CI/R conditions. It also downregulated pro-inflammatory cytokine transcription, including IL1B, IL6, and TNF. Inhibition of Nrf2 partially reversed these protective effects. In cold preservation solutions, 4-OI upregulated Nrf2 target genes such as NQO1, HMOX1, and SLC7A11. In ALI airway models, 4-OI enhanced bronchial epithelial barrier integrity and ciliary beat function after CI/R. In rat models, 4-OI administration improved lung function and reduced pulmonary edema, tissue injury, apoptosis, and systemic inflammation following extended cold preservation or non-heart-beating lung transplantation.

CONCLUSIONS

Incorporating 4-OI into cold preservation solutions appears promising for alleviating CI/R-induced bronchial epithelial injury and enhancing lung transplant outcomes via Nrf2 pathway activation.

Shenling Baizhu San improves spermatogenic dysfunction in hyperuricemia mice by regulating Sirt3/Nrf2 to inhibit testicular ferroptosis

ETHNOPHARMACOLOGICAL RELEVANCE

The effect of hyperuricemia (HUA) on testicular spermatogenesis cannot be ignored. The classical Chinese medicine compound Shenling Baizhu San (SLBZS) can reduce uric acid and improve testicular spermatogenesis, while researchers have not well explored the related pathology and pharmacodynamic mechanism have.

AIMS OF STUDY

To investigate whether the dysfunction of testicular spermatogenesis caused by HUA and the therapeutic effect of SLBZS are related to testicular cell ferroptosis.

MATERIALS AND METHODS

C57BL/6 mice and C57BL/6 background Sirt3-/- mice were induced by oxazinate potassium (OXO), and HUA spermatogenic dysfunction mice model were constructed and treated with SLBZS. Sperm quality detection and testicular histopathology served for evaluating the protective mechanism of SLBZS against testicular spermatogenesis in HUA mice. Biochemical detection, transmission electron microscopy, immunohistochemistry and immunofluorescence were used to evaluate ferroptosis level of testicular cells. Western blot analysis assisted in verifying the expression of the corresponding pathway proteins.

RESULTS

The testes of mice with HUA spermatogenic dysfunction were subjected to OXO-induced oxidative stress and ferroptosis, and the Sirt3/Nrf2 pathway-related protein expressions were changed. SLBZS improved the testes of mice with HUA spermatogenic dysfunction in terms of their spermatogenic function, oxidative stress and ferroptosis, and promoted Sirt3/Nrf2 antioxidant pathway-related proteins to be expressed. The analysis of Sirt3-/- mice was modeled and dosed, and it was found that SLBZS could not improve the spermatogenic function, oxidative stress and ferroptosis of Sirt3-deficient model mice' testes.

CONCLUSIONS

OXO-induced spermatogenic dysfunction in HUA is associated with ferroptosis of testicular cells. SLBZS can be used for treating spermatogenic dysfunction in HUA possibly by activating Sirt3/Nrf2 signaling pathway, which inhibits ferroptosis due to oxidative stress.

Shikonin protects skin cells against oxidative stress and cellular dysfunction induced by fine particulate matter

Shikonin, an herbal naphthoquinone, demonstrates a broad spectrum of pharmacological properties. Owing to increasingly adverse environmental conditions, human skin is vulnerable to harmful influences from dust particles. This study explored the antioxidant capabilities of shikonin and its ability to protect human keratinocytes from oxidative stress induced by fine particulate matter (PM2.5). We found that shikonin at a concentration of 3 µM was nontoxic to human keratinocytes and effectively scavenged reactive oxygen species (ROS) while increasing the production of reduced glutathione (GSH). Furthermore, shikonin enhanced GSH level by upregulating glutamate-cysteine ligase catalytic subunit and glutathione synthetase mediated by nuclear factor-erythroid 2-related factor. Shikonin reduced ROS levels induced by PM2.5, leading to recovering PM2.5-impaired cellular biomolecules and cell viability. Shikonin restored the GSH level in PM2.5-exposed keratinocytes via enhancing the expression of GSH-synthesizing enzymes. Notably, buthionine sulphoximine, an inhibitor of GSH synthesis, diminished effect of shikonin against PM2.5-induced cell damage, confirming the role of GSH in shikonin-induced cytoprotection. Collectively, these findings indicated that shikonin could provide substantial cytoprotection against the adverse effects of PM2.5 through direct ROS scavenging and modulation of cellular antioxidant system.

Synergistic effect in the co-extraction of Ginseng and Schisandra protein

Introduction

Ginseng and Schisandra are traditional Chinese plants that have been used in culinary practices and are renowned for their immune-boosting properties. In Chinese medicine, Ginseng and Schisandra are frequently used together as a clinical pair to mutually enhance their effect, producing a synergistic effect when consumed in combination. However, the underlying mechanism of their synergistic effect remains uncertain. Therefore, this study investigates the synergistic effect of Ginseng-Schisandra in terms of macromolecular proteins.

Methods

We used a dual-protein research methodology combined with co-extraction techniques to obtain the co-extracted protein of ginseng and Schisandra. We then compared the physicochemical and functional properties and antioxidant activities of co-extracted protein (COP), simple mixed protein (SMP), Ginseng protein (PGP), and Schisandra protein (SCP).

Results

Generally, PGP and SCP are considered as functional food with antioxidant activity. COP are composite proteins with a shared internal structure that are combined by Ginseng and Schisandra proteins, while SMP are simple mixtures of PGP and SCP. Free radical scavenging experiments indicated that COP exhibited the highest scavenging ability for hydroxyl radicals (98.89%), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals (85.95%), and 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonate) (ABTS+) radicals (42.69%). In vitro, COP significantly reduced the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA), while increasing intracellular levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and lactate dehydrogenase (LDH) levels in HepG2 cells.

Discussion

The comparative results of the macromolecular proteins reveal that COP contributes to the synergistic effect of Ginseng-Schisandra and indicate the advantages of co-extraction in protein production, suggesting the potential application of COP in the food industry.

The role and therapeutic potential of itaconate in lung disease

Lung diseases triggered by endogenous or exogenous factors have become a major concern, with high morbidity and mortality rates, especially after the coronavirus disease 2019 (COVID-19) pandemic. Inflammation and an over-activated immune system can lead to a cytokine cascade, resulting in lung dysfunction and injury. Itaconate, a metabolite produced by macrophages, has been reported as an effective anti-inflammatory and anti-oxidative stress agent with significant potential in regulating immunometabolism. As a naturally occurring metabolite in immune cells, itaconate has been identified as a potential therapeutic target in lung diseases through its role in regulating inflammation and immunometabolism. This review focuses on the origin, regulation, and function of itaconate in lung diseases, and briefly discusses its therapeutic potential.

Itaconate alleviates anesthesia/surgery-induced cognitive impairment by activating a Nrf2-dependent anti-neuroinflammation and neurogenesis via gut-brain axis

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a common neurological complication of anesthesia and surgery in aging individuals. Neuroinflammation has been identified as a hallmark of POCD. However, safe and effective treatments of POCD are still lacking. Itaconate is an immunoregulatory metabolite derived from the tricarboxylic acid cycle that exerts anti-inflammatory effects by activating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. In this study, we investigated the effects and underlying mechanism of 4-octyl itaconate (OI), a cell-permeable itaconate derivative, on POCD in aged mice.

METHODS

A POCD animal model was established by performing aseptic laparotomy in 18-month-old male C57BL/6 mice under isoflurane anesthesia while maintaining spontaneous ventilation. OI was intraperitoneally injected into the mice after surgery. Primary microglia and neurons were isolated and treated to lipopolysaccharide (LPS), isoflurane, and OI. Cognitive function, neuroinflammatory responses, as well as levels of gut microbiota and their metabolites were evaluated. To determine the mechanisms underlying the therapeutic effects of OI in POCD, ML385, an antagonist of Nrf2, was administered intraperitoneally. Cognitive function, neuroinflammatory responses, endogenous neurogenesis, neuronal apoptosis, and Nrf2/extracellular signal-related kinases (ERK) signaling pathway were evaluated.

RESULTS

Our findings revealed that OI treatment significantly alleviated anesthesia/surgery-induced cognitive impairment, concomitant with reduced levels of the neuroinflammatory cytokines IL-1β and IL-6, as well as suppressed activation of microglia and astrocytes in the hippocampus. Similarly, OI treatment inhibited the expression of IL-1β and IL-6 in LPS and isoflurane-induced primary microglia in vitro. Intraperitoneal administration of OI led to alterations in the gut microbiota and promoted the production of microbiota-derived metabolites associated with neurogenesis. We further confirmed that OI promoted endogenous neurogenesis and inhibited neuronal apoptosis in the hippocampal dentate gyrus of aged mice. Mechanistically, we observed a decrease in Nrf2 expression in hippocampal neurons both in vitro and in vivo, which was reversed by OI treatment. We found that Nrf2 was required for OI treatment to inhibit neuroinflammation in POCD. The enhanced POCD recovery and promotion of neurogenesis triggered by OI exposure were, at least partially, mediated by the activation of the Nrf2/ERK signaling pathway.

CONCLUSIONS

Our findings demonstrate that OI can attenuate anesthesia/surgery-induced cognitive impairment by stabilizing the gut microbiota and activating Nrf2 signaling to restrict neuroinflammation and promote neurogenesis. Boosting endogenous itaconate or supplementation with exogenous itaconate derivatives may represent novel strategies for the treatment of POCD.