Menaquinone-4 attenuates ferroptosis by upregulating DHODH through activation of SIRT1 after subarachnoid hemorrhage

Ginsenoside Rd alleviates early brain injury by inhibiting ferroptosis through cGAS/STING/DHODH pathway after subarachnoid hemorrhage

Ferroptosis, a recently identified form of regulated cell death, is characterized by lipid peroxidation and iron accumulation, plays a critical role in early brain injury after subarachnoid hemorrhage. Ginsenoside Rd, an active compound isolated from ginseng, is known for its neuroprotective properties. However, its influence on SAH-induced ferroptosis remains unclear. In this study, we constructed an SAH model using intravascular perforation in vivo and treated HT22 cells with oxyhemoglobin to simulate the condition in vitro. We observed significant changes in ferroptosis markers, including GPX4 and ACSL4, following SAH. Administration of ginsenoside Rd to both rats and HT22 cells effectively inhibited neuronal ferroptosis induced by SAH, alleviating neurological deficits and cognitive dysfunction in rats. Notably, the neuroprotective properties of ginsenoside Rd were countered by the STING pathway agonist 2'3'-cGAMP. Experiments conducted in vitro and in vivo illustrated that the impacts of ginsenoside Rd were counteracted by the BQR inhibitor. Our findings suggest that ginsenoside Rd mitigates EBI after SAH by suppressing neuronal ferroptosis through the cGAS/STING pathway while upregulating DHODH levels. These outcomes emphasize the potential of ginsenoside Rd as a therapeutic candidate for subarachnoid hemorrhage.

Bioinformatics Identification of angiogenesis-related biomarkers and therapeutic targets in cerebral ischemia-reperfusion

Promoting vascular endothelial cell regeneration can enhance recovery from cerebral ischemia reperfusion injury (CIRI), but there is a lack of bioinformatic studies on angiogenesis-related biomarkers in CIRI. In this study, we utilized the GSE97537 and GSE61616 datasets from GEO to identify 181 angiogenesis-related genes (ARGs) and analyzed differentially expressed genes (DEGs) between CIRI and control groups. We converted ARGs to 169 rat homologues and intersected them with DEGs to find DE-ARGs. RF and XGBoost models were employed to identify five biomarkers (Stat3, Hmox1, Egfr, Col18a1, Ptgs2) and conducted GSEA on these biomarkers, revealing their enrichment in pathways such as ECM-receptor interaction and hematopoietic cell lineage. We also analyzed the immune microenvironment, finding significant differences in 21 immune cells between CIRI and control groups. Furthermore, we constructed lncRNA-miRNA-mRNA networks and drug-gene networks. Finally, biomarker expression was compared between the CIRI and control groups by qRT-PCR in tissue and blood samples. Overall, our bioinformatic exploration of angiogenesis-related biomarkers in CIRI provides new insights for the diagnosis and treatment of CIRI.

Update on Strategies to Reduce Early Brain Injury after Subarachnoid Hemorrhage

PURPOSE OF REVIEW

Early brain injury (EBI) after aneurysmal subarachnoid hemorrhage (SAH) is the most influential clinical determinant of outcomes. Despite significant advances in understanding of the pathophysiology of EBI, currently no treatments to target EBI have been developed. This review summarizes recent advances in EBI research over the past five years with a focus on potential therapeutic targets.

RECENT FINDINGS

Mechanism-specific translational studies are converging on several pathophysiologic pathways: improved antioxidant delivery and the Sirt1/Nrf2 pathway for reactive oxygen species; NLRP3 inflammasome and microglial polarization for inflammation; and the PI3K/Akt pathway for apoptosis. Recently identified mechanistic components, such as microcirculatory failure and ferroptosis, need particular attention. Clinical studies developing radiographic markers and mechanism-specific, biofluid markers are attempting to bridge the translational therapeutic gap. There has been an exponential growth in EBI research. Further clinical studies which address specific pathophysiology mechanisms need to be performed to identify novel therapeutic approaches.

Inhibition of acid-sensing receptor GPR4 attenuates neuronal ferroptosis via RhoA/YAP signaling in a rat model of subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Subarachnoid hemorrhage (SAH) is a devastating stroke, in which acidosis is one of detrimental complications. The extracellular pH reduction can activate G protein-coupled receptor 4 (GPR4) in the brain. Yet, the extent to which proton-activated GPR4 contributes to the early brain injury (EBI) post-SAH remains largely unexplored. Ferroptosis, iron-dependent programmed cell death, has recently been shown to contribute to EBI. We aimed to investigate the effects of GPR4 inhibition on neurological deficits and neuronal ferroptosis after SAH in rats.

METHODS

A total 253 Sprague Dawley (SD) male rats (weighing 275-330g) were utilized in this study. SAH was induced by endovascular perforation. NE-52-QQ57 (NE), a selective antagonist of GPR4 was administered intraperitoneally 1-h post-SAH. To explore the mechanisms, RhoA activator U-46619 and YAP activator PY-60 were delivered intracerebroventricularly. Short- and long-term neurobehavior, SAH grading, Western blot assay, ELISA assay, immunofluorescence staining, and transmission electron microscopy was performed post-SAH.

RESULTS

Following SAH, there was an upregulation of GPR4 expression in neurons. GPR4 inhibition by NE improved both short-term and long-term neurological outcomes post-SAH. NE also reduced neuronal ferroptosis, as evidenced by decreased lipid peroxidation products 4HNE and MDA levels in brain tissues, and reduced mitochondrial shrinkage, increased mitochondria crista and decreased membrane density. The application of either U-46619 or PY-60 partially offset the neuroprotective effects of NE on neuronal ferroptosis in SAH rats.

CONCLUSIONS

This study demonstrated that acid-sensing receptor GPR4 contributed to neuronal ferroptosis after SAH via RhoA/YAP pathway, and NE may be a potential therapeutic strategy to attenuate GPR4 mediated neuronal ferroptosis and EBI after SAH.

Menaquinone-4 Alleviates Sepsis-Associated Acute Lung Injury via Activating SIRT3-p53/SLC7A11 Pathway

Background

Sepsis-associated acute lung injury (SI-ALI) is triggered by various direct or indirect noncardiogenic factors affecting the alveolar epithelium and capillary endothelial cells. Menaquinone-4 (MK-4), a major component of vitamin K, plays a crucial role as an antioxidant by effectively neutralizing reactive oxygen species (ROS) and safeguarding critical biomolecules from oxidative harm within cells. However, the specific mechanisms and clinical implications of MK-4 in SI-ALI are unclear and require further study.

Methods

Cecal ligation and puncture (CLP) surgery is a commonly used method to induce sepsis in C57BL/6N wild-type mice, and the mice were administered MK-4 at a dosage of 200 mg/kg/day and 3-TYP at 5 mg/kg/day via intraperitoneal injection for 3 days, or erastin (5 mg/kg) 0.5 hours before CLP surgery. The mice were sacrificed 24 hours after CLP surgery, and blood and lung tissue samples were collected. Pathological changes in the lung tissue and oxidative stress levels were detected. The expression levels of Sirt3, acetylated lysine, p53, SLC7A11 ALOX12 and ferroptosis-related proteins were determined. ligation and puncture (CLP).

Results

In this study, we observed that the lung inflammation was associated with reduced Sirt3 expression and increased acetylated lysine levels. The progression of SI-ALI was mitigated by MK-4 through its role in upregulating Sirt3 expression. MK-4 achieved antioxidant effects by downregulating ROS and inflammatory factor levels. Mechanistically, MK-4 inhibited the p53/SLC7A11 signalling pathway in ferroptosis by inhibiting the acetylation of p53, independent of p53 levels. In addition, MK-4 inhibited ferroptosis independent of GPX4. These findings indicate that MK-4 is a promising novel therapeutic agent for treating SI-ALI and possibly sepsis.

Conclusion

These experiments revealed that MK-4 acts as a ferroptosis suppressor, increasing the expression of Sirt3, inhibiting the p53/SLC7A11 signalling pathway, and reducing oxidative stress and inflammatory responses, thereby exerting a protective effect against ALI in sepsis.

NOX1 triggers ferroptosis and ferritinophagy, contributes to Parkinson's disease

The progressive loss of dopaminergic neurons in the midbrain is the hallmark of Parkinson's disease (PD). A newly emerging form of lytic cell death, ferroptosis, has been implicated in PD. However, it remains unclear in terms of PD-associated ferroptosis underlying causative genes and effective therapeutic approaches. This research explored the underlying mechanism of ferroptosis-related genes in PD. Here, Firstly, we found NOX1 associated with ferroptosis differently in PD patients by bioinformatics analysis. In vitro and in vivo models of PD were constructed to explore the underlying mechanism. qPCR, Western blot analysis, immunohistochemistry, immunofluorescence, Ferro orange, and BODIPY C11 were utilized to analyze the levels of ferroptosis. Transcriptomics sequencing was to investigate the downstream pathway and the analysis of immunoprecipitation to validate the upstream factor. In conclusion, NOX1 upregulation and activation of ferroptosis-related neurodegeneration, therefore, might be useful as a clinical therapeutic agent.

Menaquinone-4 alleviates hypoxic-ischemic brain damage in neonatal rats by reducing mitochondrial dysfunction via Sirt1-PGC-1α-TFAM signaling pathway

BACKGROUND

Hypoxic-ischemic encephalopathy (HIE) is a major contributor to neonatal mortality and neurodevelopmental disorders, but currently there is no effective therapy drug for HIE. Mitochondrial dysfunction plays a pivotal role in hypoxic-ischemic brain damage(HIBD). Menaquinone-4 (MK-4), a subtype of vitamin K2 prevalent in the brain, has been shown to enhance mitochondrial function and exhibit protective effects against ischemia-reperfusion injury. However, the impact and underlying molecular mechanism of MK-4 in HIE have not been fully elucidated.

METHODS

In this study, we established the neonatal rats HIBD model in vivo and oxygen-glucose deprivation and reperfusion (OGD/R) of primary neurons in vitro to explore the neuroprotective effects of MK-4 on HI damage, and illuminate the potential mechanism.

RESULTS

Our findings revealed that MK-4 ameliorated mitochondrial dysfunction, reduced oxidative stress, and prevented HI-induced neuronal apoptosis by activating the Sirt1-PGC-1α-TFAM signaling pathway through Sirt1 mediation. Importantly, these protective effects were partially reversed by EX-527, a Sirt1 inhibitor.

CONCLUSION

Our study elucidated the potential therapeutic mechanism of MK-4 in neonatal HIE, suggesting its viability as an agent for enhancing recovery from HI-induced cerebral damage in newborns. Further exploration into MK-4 could lead to novel interventions for HIE therapy.

The Interplay between Ferroptosis and Neuroinflammation in Central Neurological Disorders

Central neurological disorders are significant contributors to morbidity, mortality, and long-term disability globally in modern society. These encompass neurodegenerative diseases, ischemic brain diseases, traumatic brain injury, epilepsy, depression, and more. The involved pathogenesis is notably intricate and diverse. Ferroptosis and neuroinflammation play pivotal roles in elucidating the causes of cognitive impairment stemming from these diseases. Given the concurrent occurrence of ferroptosis and neuroinflammation due to metabolic shifts such as iron and ROS, as well as their critical roles in central nervous disorders, the investigation into the co-regulatory mechanism of ferroptosis and neuroinflammation has emerged as a prominent area of research. This paper delves into the mechanisms of ferroptosis and neuroinflammation in central nervous disorders, along with their interrelationship. It specifically emphasizes the core molecules within the shared pathways governing ferroptosis and neuroinflammation, including SIRT1, Nrf2, NF-κB, Cox-2, iNOS/NO·, and how different immune cells and structures contribute to cognitive dysfunction through these mechanisms. Researchers' findings suggest that ferroptosis and neuroinflammation mutually promote each other and may represent key factors in the progression of central neurological disorders. A deeper comprehension of the common pathway between cellular ferroptosis and neuroinflammation holds promise for improving symptoms and prognosis related to central neurological disorders.

Ferroptosis in early brain injury after subarachnoid hemorrhage: review of literature

Spontaneous subarachnoid hemorrhage (SAH), mainly caused by ruptured intracranial aneurysms, is a serious acute cerebrovascular disease. Early brain injury (EBI) is all brain injury occurring within 72 h after SAH, mainly including increased intracranial pressure, decreased cerebral blood flow, disruption of the blood-brain barrier, brain edema, oxidative stress, and neuroinflammation. It activates cell death pathways, leading to neuronal and glial cell death, and is significantly associated with poor prognosis. Ferroptosis is characterized by iron-dependent accumulation of lipid peroxides and is involved in the process of neuron and glial cell death in early brain injury. This paper reviews the research progress of ferroptosis in early brain injury after subarachnoid hemorrhage and provides new ideas for future research.