Mitochondria-derived methylmalonic acid aggravates ischemia-reperfusion injury by activating reactive oxygen species-dependent ferroptosis

Identification of novel ferroptosis-related biomarkers associated with the oxidative stress pathways in ischemic cardiomyopathy

Background

Ferroptosis is a cell death process that depends on iron and reactive oxygen species. It significantly contributes to cardiovascular diseases. However, its exact role in ischemic cardiomyopathy (ICM) is still unclear.

Methods

Using bioinformatics methods, we identified new molecular targets associated with ferroptosis in ICM and conducted various analyses-including correlation analysis, pathway enrichment analysis, protein interaction network construction, and analysis of transcription factor and drug interactions, to reveal the potential mechanisms behind these genes.

Results

We evaluated two independent training sets of ICM, GSE57338 and GSE5406, comprising 203 ICM samples, and validation sets GSE76701 to examine differentially expressed genes (DEGs) related to ferroptosis. After extracting the intersection of the gene sets and ferroptosis-related genes, 53 DEGs were identified. Enrichment analyses showed that the alterations in ferroptosis-related DEGs were mainly enriched in oxidative stress response, and immune-related pathways. Furthermore, 11 hub genes were identified using protein-protein interaction network analysis. The key interactions between 11 hub genes were more pronounced in protein localization during ICM development. In addition, we construct a hub gene and transcription factor interaction network and a small molecule drug-gene interaction network. We found that among these hub genes, the N-acetylneuraminate outer membrane channel(NANC) gene is positively correlated with most of the small-molecule drugs used to treat ICM, and its high expression might increase resistance.

Conclusions

Ferroptosis exists in ICM and and is associated with oxidative stress. This association suggests that ferroptosis may facilitate the progression of ICM.

Targeted Delivery and ROS-Responsive Release of Lutein Nanoassemblies Inhibit Myocardial Ischemia-Reperfusion Injury by Improving Mitochondrial Function

Purpose

Myocardial ischemia-reperfusion injury (MI/RI) is associated with increased oxidative damage and mitochondrial dysfunction, resulting in an elevated risk of mortality. MI/RI may be alleviated by protecting cardiomyocytes from oxidative stress. Lutein, which belongs to a class of carotenoids, has proven to be effective in cardiovascular disease treatment due to its remarkable antioxidant properties, but its application is limited due to its poor stability and low bioavailability in vivo.

Methods

In this study, a delivery system was developed based on distearoyl phosphatidyl ethanolamine (DSPE)-thiol-ketone (TK)-PEG2K (polyethylene glycol 2000) (abbreviated as DTP) and PCM-SH (CWLSEAGPVVTVRALRGTGSW) to deliver lutein (abbreviated as lutein@DTPP) to damaged myocardium. First, lutein, lutein@DTP, or lutein@DTPP were injected through the tail vein once a day for 3 days and then MI/RI model rats were established by exposing rats to ischemia for 45 min and reperfusion for 6 h. We employed a range of experimental techniques including qRT-PCR, Western blotting, transmission electron microscopy, immunohistochemistry, immunofluorescence, flow cytometry, immunoprecipitation, molecular docking, and molecular dynamics simulations.

Results

Lutein@DTPP exhibited good myocardial targeting and ROS-responsive release. Our data suggested that lutein@DTPP effectively suppresses ferroptosis in cardiomyocytes. Mechanistically, we observed an upregulation of mouse double minute-2 (MDM2) in the hearts of MI/RI models and cardiomyocytes exposed to hypoxia/reoxygenation (H/R) conditions. In addition, NADH-ubiquinone oxidoreductase 75 kDa Fe-S protein 1 (NDUFS1) translocation from the cytosol to the mitochondria was inhibited by MDM2 upregulation. Notably, no significant variation in the total NDUFS1 expression was observed in H/R-exposed cardiomyocytes following treatment with siMDM2. Further study indicated that lutein facilitates the translocation of NDUFS1 from the cytosol to mitochondria by directly binding and sequestering MDM2, thereby improving mitochondrial function and inhibiting ferroptosis.

Conclusion

Lutein@DTPP promoted the mitochondrial translocation of NDUFS1 to restore mitochondrial function and inhibited the ferroptosis of cardiomyocytes by directly binding and sequestering MDM2.

CircSpna2 attenuates cuproptosis by mediating ubiquitin ligase Keap1 to regulate the Nrf2-Atp7b signalling axis in depression after traumatic brain injury in a mouse model

BACKGROUND

Depression is a common but often overlooked consequence in individuals with post-traumatic brain injury (TBI). Circular RNAs (circRNAs) play essential roles in the nervous system, yet their involvement in the cell death mechanism known as cuproptosis and in TBI-related depression remains unclear.

OBJECTIVES

This study aimed to investigate the role of circRNA, specifically circSpna2, in the regulation of cuproptosis and its association with depression in TBI patients.

METHODS

RNA sequencing (RNA-Seq) was used to assess the differential expression of circRNAs. Depression was evaluated using subjective and objective rating scales, and circSpna2 expression levels in plasma were measured. Further functional experiments were conducted in TBI mouse models, including knockdown and overexpression of circSpna2, to explore its impact on the Keap1-Nrf2-Atp7b pathway and cuproptosis.

RESULTS

TBI patients exhibited decreased levels of circSpna2, which correlated with depression (p < 0.0001). Knocking down circSpna2 in TBI mice aggravated depression-like symptoms (p < 0.0001). Mechanistically, circSpna2 was found to bind ubiquitin ligase Keap1, modulating the Nrf2-Atp7b signaling pathway and influencing cuproptosis (docking score: -331.88). Overexpression of circSpna2 alleviated cuproptosis after TBI through the Keap1/Nrf2/Atp7b axis.

CONCLUSIONS

CircSpna2 plays a regulatory role in cuproptosis and may serve as a novel biomarker and therapeutic target for depression following TBI. Enhancing circSpna2 expression could mitigate depression after TBI by modulating the Keap1/Nrf2/Atp7b pathway.

KEY POINTS

This study explores the role of circSpna2 in depression following traumatic brain injury (TBI). It was found that circSpna2 is significantly downregulated in TBI patients, and its expression levels correlate with depressive symptoms. In TBI mouse models, overexpression of circSpna2 alleviated depression-like behaviours, while its knockdown exacerbated these symptoms, suggesting its potential as both a biomarker and a therapeutic target for post-TBI depression. Mechanistically, circSpna2 regulates the Nrf2-Atp7b signalling pathway by binding to the DGR domain of Keap1, which prevents Nrf2 ubiquitination and enhances Nrf2 activity. This in turn promotes the transcription of Atp7b, a copper transport protein, helping to maintain copper homeostasis and mitigate copper-induced oxidative stress, a key driver of cell death (cuproptosis). The overexpression of circSpna2 also improved mitochondrial function and synaptic integrity, which are typically impaired by copper dysregulation. These findings highlight the therapeutic potential of circSpna2 in managing TBI-related depression through the regulation of oxidative stress and copper homeostasis.

Iron homeostasis and ferroptosis in human diseases: mechanisms and therapeutic prospects

Iron, an essential mineral in the body, is involved in numerous physiological processes, making the maintenance of iron homeostasis crucial for overall health. Both iron overload and deficiency can cause various disorders and human diseases. Ferroptosis, a form of cell death dependent on iron, is characterized by the extensive peroxidation of lipids. Unlike other kinds of classical unprogrammed cell death, ferroptosis is primarily linked to disruptions in iron metabolism, lipid peroxidation, and antioxidant system imbalance. Ferroptosis is regulated through transcription, translation, and post-translational modifications, which affect cellular sensitivity to ferroptosis. Over the past decade or so, numerous diseases have been linked to ferroptosis as part of their etiology, including cancers, metabolic disorders, autoimmune diseases, central nervous system diseases, cardiovascular diseases, and musculoskeletal diseases. Ferroptosis-related proteins have become attractive targets for many major human diseases that are currently incurable, and some ferroptosis regulators have shown therapeutic effects in clinical trials although further validation of their clinical potential is needed. Therefore, in-depth analysis of ferroptosis and its potential molecular mechanisms in human diseases may offer additional strategies for clinical prevention and treatment. In this review, we discuss the physiological significance of iron homeostasis in the body, the potential contribution of ferroptosis to the etiology and development of human diseases, along with the evidence supporting targeting ferroptosis as a therapeutic approach. Importantly, we evaluate recent potential therapeutic targets and promising interventions, providing guidance for future targeted treatment therapies against human diseases.

Ferroptosis and myocardial ischemia-reperfusion: mechanistic insights and new therapeutic perspectives

Myocardial ischemia-reperfusion injury (MIRI) is a significant factor in the development of cardiac dysfunction following a myocardial infarction. Ferroptosis, a type of regulated cell death driven by iron and marked by lipid peroxidation, has garnered growing interest for its crucial involvement in the pathogenesis of MIRI.This review comprehensively examines the mechanisms of ferroptosis, focusing on its regulation through iron metabolism, lipid peroxidation, VDAC signaling, and antioxidant system dysregulation. We also compare ferroptosis with other forms of cell death to highlight its distinct characteristics. Furthermore, the involvement of ferroptosis in MIRI is examined with a focus on recent discoveries concerning ROS generation, mitochondrial impairment, autophagic processes, ER stress, and non-coding RNA regulation. Lastly, emerging therapeutic strategies that inhibit ferroptosis to mitigate MIRI are reviewed, providing new insights into potential clinical applications.

Healthy Plasma Exosomes Exert Potential Neuroprotective Effects against Methylmalonic Acid-Induced Hippocampal Neuron Injury

Exosomes have shown good potential for alleviating neurological deficits and delaying memory deterioration, but the neuroprotective effects of exosomes remain unknown. Methylmalonic acidemia is a metabolic disorder characterized by the accumulation of methylmalonic acid (MMA) in various tissues that inhibits neuronal survival and function, leading to accelerated neurological deterioration. Effective therapies to mitigate these symptoms are lacking. The purpose of this study was to explore the neuroprotective effects of plasma exosomes on cells and a mouse model of MMA-induced injury. We evaluated the ability of plasma exosomes to reduce the neuronal apoptosis, cross the blood-brain barrier, and affect various parameters related to neuronal function. MMA promoted cell apoptosis, disrupted the metabolic balance, and altered the expression of B-cell lymphoma-2 (Bcl-2), Bcl2-associated X (Bax), and synaptophysin-1 (Syp-1), and these changes may be involved in MMA-induced neuronal apoptosis. Additionally, plasma exosomes normalized learning and memory and protected against MMA-induced neuronal apoptosis. Our findings indicate that neurological deficits are linked to the pathogenesis of methylmalonic acidemia, and healthy plasma exosomes may exert neuroprotective and therapeutic effects by altering the expression of exosomal microRNAs, facilitating neuronal functional recovery in the context of this inherited metabolic disease. Intravenous plasma-derived exosome treatment may be a novel clinical therapeutic strategy for methylmalonic acidemia.

Saikosaponins Targeting Programmed Cell Death as Anticancer Agents: Mechanisms and Future Perspectives

Saikosaponins (SS), which are major bioactive compounds in Radix Bupleuri, have long been used clinically for multicomponent, multitarget, and multipathway therapeutic strategies. Programmed cell death (PCD) induction is among the multiple mechanisms of SS and mediates the anticancer efficacy of this drug family. Although SS show promise for anticancer therapy, the available data to explain how SS mediate their key anticancer effects through PCD (apoptosis, autophagy, ferroptosis, and pyroptosis) remain limited and piecemeal. This review offers an extensive analysis of the key pathways and mechanisms involved in PCD and explores the importance of SS in cancer. We believe that high-quality clinical trials and a deeper understanding of the pharmacological targets involved in the signalling cascades that govern tumour initiation and progression are needed to facilitate the development of innovative SS-based treatments. Elucidating the specific anticancer pathways activated by SS and further clarifying how comprehensive therapies lead to cross-link among the different types of cell death will inspire the clinical translation of SS as cancer treatments.

Decreased cobalamin sensitivity and biological aging acceleration in the general population

BACKGROUND

The evidence on the association between cobalamin (Cbl) and aging or relevant outcomes is limited and controversial. We aimed to investigate the relationships between cobalamin intake- and function-related biomarkers and biological aging.

METHODS

The study encompassed 22,812 participants aged 20 years and older from the National Health and Nutrition Examination Survey. A panel of biomarkers or algorithms was used to assess biological aging, including Klemera-Doubal Age Acceleration (KDMAccel), Phenotypic age acceleration (PhenoAgeAccel), telomere length, α-Klotho, and PhenoAge advancement. Weighted generalized linear regression analysis was used to assess the associations between cobalamin-intake biomarkers (serum cobalamin, cobalamin intake from food, cobalamin supplement use, serum methylmalonic acid [MMA], and homocysteine [Hcy]) and function-related biomarkers (functional cobalamin deficiency and cobalamin insensitivity index).

RESULTS

Among the 22,812 individuals, the weighted mean (SE) age was 48.3 (0.2) years and 48.0% were males. Unexpectedly, serum and dietary cobalamin as well as serum MMA and Hcy levels were positively associated with most indicators of biological aging. Cobalamin sensitivity was assessed by the combination of binary Cbllow/high and MMAlow/high or Hcylow/high (cutoff values: 400 pg/mL for cobalamin, 250 nmol/L for MMA, and 12.1 μmol/l for Hcy) and a newly constructed cobalamin insensitivity index (based on the multiplicative term of serum cobalamin and serum MMA or Hcy). The multivariable-adjusted β (95%CIs) of KDMAccel in the MMAlowCbllow, MMAlowCblhigh, MMAhighCbllow, and MMAhighCblhigh groups were reference, 0.27 (0.03 to 0.51), 0.85 (0.41 to 1.29), and 7.97 years (5.77 to 10.17) respectively, which were consistent for the combination of serum Hcy and cobalamin. Both cobalamin insensitivity indices were robustly associated with biological aging acceleration in a dose-response pattern (each p < 0.001).

CONCLUSIONS

Decreased cobalamin sensitivity but not cobalamin insufficiency might be associated with biological aging acceleration. Further studies would improve understanding of the underlying mechanisms between decreased cobalamin sensitivity and biological aging acceleration.

Research progress on ferroptosis in the pathogenesis and treatment of neurodegenerative diseases

Globally, millions of individuals are impacted by neurodegenerative disorders including Huntington's disease (HD), amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), and Alzheimer's disease (AD). Although a great deal of energy and financial resources have been invested in disease-related research, breakthroughs in therapeutic approaches remain elusive. The breakdown of cells usually happens together with the onset of neurodegenerative diseases. However, the mechanism that triggers neuronal loss is unknown. Lipid peroxidation, which is iron-dependent, causes a specific type of cell death called ferroptosis, and there is evidence its involvement in the pathogenic cascade of neurodegenerative diseases. However, the specific mechanisms are still not well known. The present article highlights the basic processes that underlie ferroptosis and the corresponding signaling networks. Furthermore, it provides an overview and discussion of current research on the role of ferroptosis across a variety of neurodegenerative conditions.