Ferroptosis: a cell death connecting oxidative stress, inflammation and cardiovascular diseases

Ferroptosis contribute to neonicotinoid imidacloprid-evoked pyroptosis by activating the HMGB1-RAGE/TLR4-NF-κB signaling pathway

Imidacloprid (IMI) is among the common neonicotinoid insecticides used in agriculture worldwide, posing a potential toxic threat to non-target animals and humans. Numerous studies have shown that ferroptosis is involved in the pathophysiological progression of renal diseases. However, it remains unclear whether ferroptosis is involved in IMI-induced nephrotoxicity. In the present study, we investigated the potential pathogenic role of ferroptosis in IMI-induced kidney damage in vivo. Transmission electron microscopy (TEM) showed that the mitochondrial crest of kidney cells significantly decreased following IMI exposure. Moreover, IMI exposure triggered ferroptosis and lipid peroxidation in the kidney. We confirmed that nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated antioxidant capability was negatively correlated with the ferroptosis induced by IMI exposure. Importantly, we verified that NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3)-driven inflammation occurred in the kidneys following IMI exposure, but pretreatment with the ferroptosis inhibitor ferrostatin (Fer-1) blocked this phenomenon. Additionally, IMI exposure induced F4/80⁺ macrophages to accumulated in the proximal tubules of the kidneys, and also increased the protein expression of high-mobility group box 1 (HMGB1), receptor for advanced glycation end products (RAGE), receptor for advanced glycation end products (TLR4), and nuclear factor kappa-B (NF-κB). In contrast, inhibition of ferroptosis by Fer-1 blocked IMI-induced NLRP3 inflammasome activation, F4/80 positive macrophages, and the HMGB1-RAGE/TLR4 signaling pathway. To the best of our knowledge, this is the first study to reveal that IMI stress can induce Nrf2 inactivation, thereby triggering ferroptosis, causing an initial wave of death, and activating HMGB1-RAGE/TLR4 signaling, which promotes pyroptosis that perpetuates kidney dysfunction.

The role of the ferroptosis pathway in the regulation of polysaccharides for human health: A review

Polysaccharides are natural polymers with ketone or aldehyde groups that are widely found in plants, animals, and microorganisms. They exhibit various biological activities and have potential development value in the food and pharmaceutical fields. Ferroptosis is a recently discovered modality that modulates cell death and has attracted considerable attention because it is considered to be involved in many pathophysiological processes. The inhibition of ferroptosis by reducing intracellular iron accumulation and lipid peroxidation may provide potential protective strategies against related pathologies. Ferroptosis is also involved in the physiological activities of polysaccharides, and its regulatory mechanism varies according to different physiological activities. However, a systematic summary on the involvement of ferroptosis in the physiological activities of polysaccharides is currently lacking. Therefore, this review systematically summarized the relationship between the physiological activities of polysaccharides and ferroptosis and focused on the regulatory mechanism of ferroptosis, with respect to the anti-cancer, anti-inflammatory, antioxidant, and immunomodulatory activities of all polysaccharides. The primary objective was to find new polysaccharide-related therapeutic breakthroughs for related diseases and to provide a reference for further research on polysaccharides-based therapeutics.

The Emerging Role of Heat Shock Factor 1 (HSF1) and Heat Shock Proteins (HSPs) in Ferroptosis

Cells employ a well-preserved physiological stress response mechanism, termed the heat shock response, to activate a certain type of molecular chaperone called heat shock proteins (HSPs). HSPs are activated by transcriptional activators of heat shock genes known as heat shock factors (HSFs). These molecular chaperones are categorized as the HSP70 superfamily, which includes HSPA (HSP70) and HSPH (HSP110) families; the DNAJ (HSP40) family; the HSPB family (small heat shock proteins (sHSPs)); chaperonins and chaperonin-like proteins; and other heat-inducible protein families. HSPs play a critical role in sustaining proteostasis and protecting cells against stressful stimuli. HSPs participate in folding newly synthesized proteins, holding folded proteins in their native conformation, preventing protein misfolding and accumulation, and degrading denatured proteins. Ferroptosis is a recently identified type of oxidative iron-dependent cell demise. It was coined recently in 2012 by Stockwell Lab members, who described a special kind of cell death induced by erastin or RSL3. Ferroptosis is characterized by alterations in oxidative status resulting from iron accumulation, increased oxidative stress, and lipid peroxidation, which are mediated by enzymatic and non-enzymatic pathways. The process of ferroptotic cell death is regulated at multiple, and it is involved in several pathophysiological conditions. Much research has emerged in recent years demonstrating the involvement of HSPs and their regulator heat shock factor 1 (HSF1) in ferroptosis regulation. Understanding the machinery controlling HSF1 and HSPs in ferroptosis can be employed in developing therapeutic interventions for ferroptosis occurrence in a number of pathological conditions. Therefore, this review comprehensively summarized the basic characteristics of ferroptosis and the regulatory functions of HSF1 and HSPs in ferroptosis.

Identification and validation of ferroptosis-related genes for chronic rhinosinusitis with nasal polyps

PURPOSE

Even though the great progress in the field of chronic rhinosinusitis with nasal polyps (CRSwNP) has been achieved, ferroptosis and its molecular mechanism in CRSwNP remain blank. We are the first to study the relationship between CRSwNP and ferroptosis, aiming to identify ferroptosis-related genes in the process of CRSwNP.

METHODS

Using the GEO database and the FerrDb database, significantly differentially expressed ferroptosis-related genes (DEFGs) were selected between CRSwNP-NP and CRSwNP-IT specimens. Then, the protein-protein interaction (PPI) network of ferroptosis-related genes was constructed. Functional enrichment analyses (GSVA, GO, KEGG, and GeneCodis analyses) were introduced in our study. Besides, based on the GSE136825 data set, DEFGs between CRSwNP-NP and CS-IT specimens were also analyzed. Finally, qRT-PCR was performed to validate the selected ferroptosis-related genes with clinical samples.

RESULTS

31 significantly DEFGs were identified between CRSwNP-NP and CRSwNP-IT specimens. Functional enrichment analyses and the analysis of GeneCodis 4 pointed out that DEFGs may potentially be involved in some related KEGG pathways. 8 DEFGs were selected between CRSwNP-NP and CS-IT specimens. The experimental verification indicated that 4 genes (GPX2, CDO1, CAV1, and TP53) were the important DEFGs of CRSwNP. The Venn diagrams proved that CDO1 and GPX2 were considered as the most important DEFGs genes of CRSwNP, especially GPX2.

CONCLUSIONS

Though a comprehensive bioinformatics analysis and the experimental verification, CDO1 and GPX2 were considered as the important ferroptosis-related genes of CRSwNP, especially GPX2. However, further molecular biological experiments would be still required to uncover the underlying mechanism between ferroptosis and CRSwNP.

GPX4 utilization by selenium is required to alleviate cadmium-induced ferroptosis and pyroptosis in sheep kidney

Cadmium (Cd), a persistent and harmful heavy metal in the environment, can accumulate in the kidneys and cause nephrotoxicity. Selenium (Se) is a beneficial natural element that alleviates the toxicity of Cd. To ascertain the relationship between the protective mechanism of Se against Cd nephrotoxicity and ferroptosis and pyroptosis, we randomly divided 48 sheep into four groups and treated them with Cd chloride and/or sodium selenite for 50 days. The data confirmed that Cd apparently resulted in impaired kidney histology and function, depletion of GSH and nicotinamide adenine dinucleotide phosphate contents and CAT and SOD activities, elevation of MDA level, as well as the reduction in selenoprotein mRNA (GPX1, GPX4, TXNRD1, SELP) levels and GPX4 protein level and immunofluorescence intensity. Meanwhile, Cd induced ferroptosis by causing iron overload, up-regulating PTGS2, NCOA4, TFR1, and LC3B mRNA levels and PTGS2 and LC3B-II/LC3B-I protein levels, reducing SLC7A11 and FTH1 mRNA and protein levels, and enhancing the immunofluorescence co-localization of FTH1/LC3B. Moreover, it was also found that Cd triggered pyroptosis, which was evidenced by the increase of NLRP3 immunohistochemical positive signal, GSDMD-N immunofluorescence intensity, IL-1β and IL-18 release and the levels of pyroptosis-related mRNA (NLRP3, ASC, Caspase-1, GSDMD, IL-1β and IL-18) and proteins (NLRP3, Caspase-1p20, GSDMD-N, IL-1β and IL-18). Notably, Se increased the expression level of GPX4 and the transcription factors TFAP2c and SP1, and ameliorated Cd-induced changes in aforementioned factors. In conclusion, GPX4 utilization by Se might be required to alleviate Cd-induced ferroptosis and pyroptosis in sheep kidney.

PRDX6-mediated pulmonary artery endothelial cell ferroptosis contributes to monocrotaline-induced pulmonary hypertension

BACKGROUND

Pulmonary hypertension (PH) is a life-threatening cardiopulmonary disorder whose underlying pathogenesis is unknown. Our previous study showed that pulmonary endothelial cell (PAEC) ferroptosis is involved in the progression of PH by releasing High-mobility group box 1 (HMGB1) and activating Toll-like receptor 4/NOD-like receptor family pyrin domain containing 3 (TLR4/NLRP3) inflammasome signalling. The precise mechanisms that regulate ferroptosis in PH are unclear. This study aimed to investigate the effect of peroxiredoxin 6 (PRDX6) on PAEC ferroptosis in PH.

METHODS

A rat model of PH was established with monocrotaline (MCT), and the distribution and expression of PRDX6 in the pulmonary artery were examined. Lentiviral vectors carrying PRDX6 (LV-PRDX6) were transfected into PAECs and injected into MCT-induced PH rats. Cell viability, MDA levels, reactive oxygen species (ROS) levels, labile iron pool (LIP) levels and mitochondrial morphology were examined. Ferroptosis-related proteins (NADPH oxidase-4 (NOX4), glutathione peroxidase 4 (GPX4), and ferritin heavy chain 1(FTH1)), TLR4, NLRP3 inflammasome markers, HMGB1 and inflammatory cytokines were examined. Pulmonary vascular remodelling and right ventricular structure and function were measured.

RESULTS

PRDX6 was expressed in PAECs and was significantly decreased in PH. PRDX6 overexpression significantly inhibited ferroptosis in PAECs under PH conditions in vitro and in vivo, as indicated by increased cell viability, decreased MDA, ROS and LIP levels, inhibited mitochondrial damage, upregulated GPX4 and FTH1 expression, and downregulated NOX4 expression. PRDX6 overexpression attenuated pulmonary vascular remodelling and changes in right ventricle structure and function in MCT-induced PH rats. Moreover, PRDX6 overexpression prevented HMGB1 release by PAECs and decreased TLR4 and NLRP3 inflammasome expression and inflammatory cytokine release in macrophages, while RSL3, a specific activator of ferroptosis, reversed these effects.

CONCLUSIONS

Taken together, these findings indicate that PRDX6 regulates PAEC ferroptosis through the release of HMGB1 and activation of the TLR4/NLRP3 inflammasome signalling pathway, providing novel therapeutic targets for the treatment of PH.

Alzheimer’s disease: insights and new prospects in disease pathophysiology, biomarkers and disease-modifying drugs

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases that affect millions of people worldwide, with both prevalence and incidence increasing with age. It is characterized by cognitive decline associated, specifically, with degeneration of cholinergic neurons. The problem of this disease is even more fundamental as the available therapies remain fairly limited and mainly focused on symptoms' relief. Although the aetiology of the disease remains elusive, two main pathological hallmarks are described: i) presence of neurofibrillary tangles formed by unfolded protein aggregates (hyperphosphorylated Tau protein) and ii) presence of extracellular aggregates of amyloid-beta peptide. Given the complexity surrounding the pathogenesis of the disease, several potential targets have been highlighted and interrelated upon its progression, such as oxidative stress and the accumulation of metal ions. Thus, advances have been made on the development of innovative multitarget therapeutical compounds to delay the disease progression and restore cell function. This review focuses the ongoing research on new insights and emerging disease-modifying drugs for AD treatment. Furthermore, classical and novel potential biomarkers for early diagnosis of the disease, and their role in assisting on the improvement of targeted therapies will also be approached.

Ferroptosis Is Involved in Sex-Specific Small Intestinal Toxicity in the Offspring of Adult Mice Exposed to Polystyrene Nanoplastics during Pregnancy

Nanoplastics are common contaminants in the living environment. Thus far, no investigations have focused on small intestinal injury in the offspring of adult mice that were exposed to nanoplastics through the respiratory system during pregnancy. Here, we evaluated potential intestinal injury in the offspring of adult mice that were subjected to maternal 80 nm polystyrene nanoparticle (PS-NP) exposure during gestation. PS-NP exposure significantly reduced the birth weight of female mice compared with male mice. However, the adult body weights of the female and male offspring were substantially greater in the PS-NP-exposed groups. Additionally, we found that exposure to PS-NPs during pregnancy caused histological changes in the small intestines of both female and male offspring. Mechanistic analysis revealed upregulation of reactive oxygen species in the small intestines, as indicated by changes in the levels of superoxide dismutase (SOD) and malondialdehyde (MDA). Furthermore, exposure to PS-NPs led to downregulation of GPx4, FTH1, and FTL protein levels, indicating initiation of ferroptosis. Notably, the changes in mRNA expression levels of GPx4, FTH1, and FTL differed between female and male offspring. Although all phenotypes failed to demonstrate classic dose-dependent effects, the data imply that small intestinal toxicity is greater in female offspring than in male offspring. Our results suggest that PS-NP exposure during pregnancy causes sex-specific small intestinal toxicity, which might contribute to reactive oxygen species activation and subsequent ferroptosis. Overall, this study showed toxic effects in offspring after PS-NP exposure during pregnancy.

Pharmacological Modulations of Nrf2 and Therapeutic Implications in Aneurysmal Subarachnoid Hemorrhage

An aneurysmal subarachnoid hemorrhage (aSAH) is a subtype of stroke with high morbidity and mortality. The main causes of a poor prognosis include early brain injury (EBI) and delayed vasospasm, both of which play a significant role in the pathophysiological process. As an important mechanism of EBI and delayed vasospasm, oxidative stress plays an important role in the pathogenesis of aSAH by producing reactive oxygen species (ROS) through the mitochondria, hemoglobin, or enzymatic pathways in the early stages of aSAH. As a result, antioxidant therapy, which primarily targets the Nrf2-related pathway, can be employed as a potential strategy for treating aSAH. In the early stages of aSAH development, increasing the expression of antioxidant enzymes and detoxifying enzymes can relieve oxidative stress, reduce brain damage, and improve prognosis. Herein, the regulatory mechanisms of Nrf2 and related pharmacological compounds are reviewed, and Nrf2-targeted drugs are proposed as potential treatments for aSAH.

Competing endogenous RNA network analysis of the molecular mechanisms of ischemic stroke

BACKGROUND

Ischemic stroke (IS) is a serious neurological disease that largely results in long-term disability and death. Extensive evidence has indicated that the activation of inflammation and ferroptosis significantly contribute to the development of IS pathology. However, the underlying molecular mechanism remains unclear. In this study, we aimed to identify potential biomarkers associated with IS through the construction of a competing endogenous RNA (ceRNA) network and to investigate the possible inflammatory and ferroptosis-related molecular mechanisms.

RESULTS

We identified 178 differentially expressed target messenger RNAs (DETmRNAs) associated with IS. As revealed through enrichment analysis, the DEmRNAs were mainly enriched in the inflammatory signaling pathways and also related to ferroptosis mechanism. The CIBERSORT algorithm showed immune infiltration landscapes in which the naïve B cells, naïve T cells, and monocytes had statistically different numbers in the cerebral infarction group compared with the control group. A ceRNA network was constructed in this study involving 44 long non-coding RNAs (lncRNAs), 15 microRNAs (miRNAs), and 160 messenger RNAs (mRNAs). We used the receiver operating characteristic (ROC) analysis to identify three miRNAs (miR-103a-3p, miR-140-3p, and miR-17-5p), one mRNA (TLR4), and one lncRNA (NEAT1) as the potential key biomarkers of the ceRNA network. The key mRNA and lncRNA were shown to be highly related to the ferroptosis mechanism of IS. The expression of these key biomarkers was also further validated by a method of quantitative real-time polymerase chain reaction in SH-SY5Y cells, and the validated results were consistent with the findings predicted by bioinformatics.

CONCLUSION

Our results suggest that the ceRNA network may exert an important role in the inflammatory and ferroptosis molecular mechanisms of IS, providing new insight into therapeutic IS targets.

Depletion of SOD2 enhances nasopharyngeal carcinoma cell radiosensitivity via ferroptosis induction modulated by DHODH inhibition

BACKGROUND

Recurrence due to the development of radioresistance remains a major challenge in the clinical management of nasopharyngeal carcinoma. The objective of this study was to increase the sensitivity of nasopharyngeal carcinoma cells to ionizing radiation by enhancing oxidative stress and ferroptosis caused by disrupting the mitochondrial anti-oxidant enzyme system.

METHODS

Oxidative stress cell model was constructed by SOD2 knockdown using shRNA. The expression and activity of DHODH was suppressed by siRNA and brequinar in SOD2 depleted cells. Protein levels were determined by western blotting and ferroptosis was assessed by C11 BODIPY and malondialdehyde assay. Cell viability was evaluated using CCK-8 assay while radiotoxicity was assessed by colony formation assay. Cellular ATP level was determined by ATP assay kits, ROS was determined by DCFD and DHE, while mitochondrial oxygen consumption was determined by seahorse assay. Data were analyzed by two-tailed independent t-test.

RESULTS

Radiation upregulated SOD2 expression and SOD2 depletion increased cellular O₂^.-, malondialdehyde, and the fluorescence intensity of oxidized C11 BODIPY. It also resulted in mitochondrial damage. Its depletion decreased colony formation both under ionizing and non-ionizing radiation conditions. The ferroptosis inhibitor, deferoxamine, rescued cell viability and colony formation in SOD2 depleted cells. Cellular level of malondialdehyde, fluorescence intensity of oxidized C11 BODIPY, O₂^.- level, ATP, and mitochondrial oxygen consumption decreased following DHODH inhibition in SOD2 depleted cells. Cell viability and colony formation was rescued by DHODH inhibition in SOD2 depleted cells.

CONCLUSION

Inducing oxidative stress by SOD2 inhibition sensitized nasopharyngeal carcinoma cells to ionizing radiation via ferroptosis induction. This was found to be dependent on DHODH activity. This suggests that DHODH inhibitors should be used with caution during radiotherapy in nasopharyngeal carcinoma patients.

Iron Metabolism in Cardiovascular Disease: Physiology, Mechanisms, and Therapeutic Targets

The cardiovascular system requires iron to maintain its high energy demands and metabolic activity. Iron plays a critical role in oxygen transport and storage, mitochondrial function, and enzyme activity. However, excess iron is also cardiotoxic due to its ability to catalyze the formation of reactive oxygen species and promote oxidative damage. While mammalian cells have several redundant iron import mechanisms, they are equipped with a single iron-exporting protein, which makes the cardiovascular system particularly sensitive to iron overload. As a result, iron levels are tightly regulated at many levels to maintain homeostasis. Iron dysregulation ranges from iron deficiency to iron overload and is seen in many types of cardiovascular disease, including heart failure, myocardial infarction, anthracycline-induced cardiotoxicity, and Friedreich's ataxia. Recently, the use of intravenous iron therapy has been advocated in patients with heart failure and certain criteria for iron deficiency. Here, we provide an overview of systemic and cellular iron homeostasis in the context of cardiovascular physiology, iron deficiency, and iron overload in cardiovascular disease, current therapeutic strategies, and future perspectives.

3-Carboxy-4-methyl-5-propyl-2-furanpropanoic acid (CMPF) induces cell death through ferroptosis and acts as a trigger of apoptosis in kidney cells

Ferroptosis is a cell death mechanism characterized by intracellular iron accumulation and lipid peroxidation. Effects of uremic toxins on ferroptosis in the kidney are not well understood. We investigated whether protein-bound uremic toxins induce ferroptosis, resulting in cell death, using the bilateral ureteral obstruction (BUO) mouse model and kidney cells. In BUO mice, we observed elevated lipid peroxidation, increased iron concentration, and decreased glutathione peroxidase 4 (GPX4) expression. Levels of transferrin receptor 1 and system Xc-, which are involved in iron transport and storage, were also elevated, while those of ferritin heavy and light chains (FHC and FLC) were reduced. Treatment of HK-2 and NRK49F kidney cells with CMPF decreased GSH levels and the expression of GPX4, FHC, and FLC, and increased levels of ROS, lipid peroxidation, and intracellular iron concentration. CMPF-induced and erastin-induced decreases in GPX4 levels and increases in Bax and cytochrome C levels were counteracted by ferrostatin-1 pretreatment. However, GPX4 mRNA levels, protein abundance, or promoter activity were not restored by Z-VAD-FMK, a multi-caspase inhibitor. These results suggest that ferroptosis induced by CMPF treatment induces apoptosis, and inhibition of ferroptosis reduces apoptosis, suggesting that ferroptosis plays a role in triggering cell death by apoptosis.

Dysregulation of Iron Metabolism-Linked Genes at Myocardial Tissue and Cell Levels in Dilated Cardiomyopathy

In heart failure, the biological and clinical connection between abnormal iron homeostasis, myocardial function, and prognosis is known; however, the expression profiles of iron-linked genes both at myocardial tissue and single-cell level are not well defined. Through publicly available bulk and single-nucleus RNA sequencing (RNA-seq) datasets of left ventricle samples from adult non-failed (NF) and dilated cardiomyopathy (DCM) subjects, we aim to evaluate the altered iron metabolism in a diseased condition, at the whole cardiac tissue and single-cell level. From the bulk RNA-seq data, we found 223 iron-linked genes expressed at the myocardial tissue level and 44 differentially expressed between DCM and NF subjects. At the single-cell level, at least 18 iron-linked expressed genes were significantly regulated in DCM when compared to NF subjects. Specifically, the iron metabolism in DCM cardiomyocytes is altered at several levels, including: (1) imbalance of Fe³⁺ internalization (SCARA5 down-regulation) and reduction of internal conversion from Fe³⁺ to Fe²⁺ (STEAP3 down-regulation), (2) increase of iron consumption to produce hemoglobin (HBA1/2 up-regulation), (3) higher heme synthesis and externalization (ALAS2 and ABCG2 up-regulation), (4) lower cleavage of heme to Fe²⁺, biliverdin and carbon monoxide (HMOX2 down-regulation), and (5) positive regulation of hepcidin (BMP6 up-regulation).

The ferroptosis in haemocytes of Pacific oyster Crassostrea gigas upon erastin treatment

Ferroptosis is an iron and oxidative dependent form of cell death usually mediated by redox related molecules in vertebrates. In the present study, a glutathione peroxidase 4 (GPX4) and a solute carrier family 7 member 11 (SLC7A11, xCT) homologues were identified from the oyster Crassostrea gigas (designed as CgGPX4 and CgxCT), which contained a GSHPx domain and an AA_permease domain, respectively. The mRNA transcripts of CgGPX4 and CgxCT were expressed in all the examined tissues, including gill, gonad, adductor muscle, labial palp, mantle, hepatopancreas and haemocytes, with the highest expression in haemocytes. After erastin treatment, the rate of cell malformation and cell death increased significantly in haemocytes, and the mitochondrial atrophy, crest loss and fracture were observed in haemocytes. While the amount of Fe²⁺ and Malondialdehyde (MDA) increased significantly, the mRNA expressions of CgGPX4, CgxCT and voltage-dependent anion channel 2 (CgVDAC2) in haemocytes decreased significantly after erastin treatment. These results indicated that erastin was able to induce the ferroptosis of oyster haemocytes.

COVID-19 Causes Ferroptosis and Oxidative Stress in Human Endothelial Cells

Oxidative stress and endothelial dysfunction have been shown to play crucial roles in the pathophysiology of COVID-19 (coronavirus disease 2019). On these grounds, we sought to investigate the impact of COVID-19 on lipid peroxidation and ferroptosis in human endothelial cells. We hypothesized that oxidative stress and lipid peroxidation induced by COVID-19 in endothelial cells could be linked to the disease outcome. Thus, we collected serum from COVID-19 patients on hospital admission, and we incubated these sera with human endothelial cells, comparing the effects on the generation of reactive oxygen species (ROS) and lipid peroxidation between patients who survived and patients who did not survive. We found that the serum from non-survivors significantly increased lipid peroxidation. Moreover, serum from non-survivors markedly regulated the expression levels of the main markers of ferroptosis, including GPX4, SLC7A11, FTH1, and SAT1, a response that was rescued by silencing TNFR1 on endothelial cells. Taken together, our data indicate that serum from patients who did not survive COVID-19 triggers lipid peroxidation in human endothelial cells.

Qing-Xin-Jie-Yu Granule inhibits ferroptosis and stabilizes atherosclerotic plaques by regulating the GPX4/xCT signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Qing-Xin-Jie-Yu Granule (QXJYG) is an integrated traditional Chinese medicine formula used to treat atherosclerotic (AS) cardiovascular diseases. A randomized controlled trial found that QXJYG reduced cardiovascular events and experiments also verified that QXJYG attenuated AS by remodeling the intestinal flora.

AIM OF THE STUDY

To determine whether QXJYG would attenuate AS and plaque vulnerability by regulating ferroptosis in high-fat diet-induced atherosclerotic ApoE-/- mice and to investigate the effects of QXJYG on macrophage ferroptosis in RAS-selective lethal 3 (RSL3)-induced J744A.1 cells.

METHODS

AS models in ApoE-/- mice and RSL3-induced ferroptosis in J744A.1 cells were established to measure the protective and anti-ferroptotic effects of QXJYG in vivo and in vitro. The glutathione peroxidase 4 (GPX4)/cystine glutamate reverse transporter (xCT) signal pathway was examined by immunohistochemistry and western blotting.

RESULTS

QXJYG attenuated AS progression and plaque vulnerability. Characteristic morphological changes of ferroptosis in the QXJYG-treated animals were rare. Total iron was significantly lower in the QXJYG group than in the model group (P < 0.05); QXJYG suppressed the lipid peroxidation (LPO) levels (malondialdehyde), enhanced the antioxidant capacity (superoxide dismutase and glutathione), and reduced inflammatory factors (interleukin [IL]-6, IL-1β, tumor necrosis factor-α) associated with ferroptosis. Expression of GPX4/xCT in aorta tissues was remarkably increased in the QXJYG group. QXJYG inhibited ferroptosis in J744A.1 macrophages disturbed using RSL3. The Fe2+, LPO, and reactive oxygen species levels were lower in the QXJYG group than in the RSL3 group (P < 0.05). The QXJYG group showed higher expression of the GPX4/xCT signal pathway.

CONCLUSION

QXJYG inhibits ferroptosis in vulnerable AS plaques partially via the GPX4/xCT signaling pathway.

Pterostilbene Confers Protection against Diquat-Induced Intestinal Damage with Potential Regulation of Redox Status and Ferroptosis in Broiler Chickens

Oxidative stress causes damage to macromolecules, including proteins, DNA, and lipid, and has been recognized as a crucial driver of the onset and progression of several intestinal disorders. Pterostilbene, one of the natural antioxidants, has attracted considerable attention owing to its multiple biological activities. In the present study, we established an oxidative stress model in broiler chickens via injection with diquat to investigate whether pterostilbene could attenuate diquat-induced intestinal damage and reveal the underlying mechanisms. We found that diquat-induced decreases in the activities of superoxide dismutase and glutathione peroxidase and the level of reduced glutathione and the increase in hydrogen peroxide content in plasma and jejunum were significantly alleviated by pterostilbene (P < 0.05). Pterostilbene supplementation also decreased intestinal permeability and jejunal apoptosis rate, improved jejunal villus height and the ratio of villus height to crypt depth, and promoted the transcription and translation of jejunal tight junction proteins occludin and zona occludens 1 in diquat-challenged broilers (P < 0.05). Furthermore, pterostilbene reversed diquat-induced mitochondrial injury in the jejunum, as indicated by the decreased reactive oxygen species level and elevated activities of superoxide dismutase 2 and mitochondrial respiratory complexes (P < 0.05). Importantly, administering pterostilbene maintained iron homeostasis, inhibited lipid peroxidation, and regulated the expression of the markers of ferroptosis in the jejunum of diquat-exposed broilers (P < 0.05). The nuclear factor erythroid 2-related factor 2 signaling pathway in the jejunum of diquat-exposed broilers was also activated by pterostilbene (P < 0.05). In conclusion, our study provides evidence that pterostilbene alleviates diquat-induced intestinal mucosa injury and barrier dysfunction by strengthening antioxidant capacity and regulating ferroptosis of broiler chickens.

Targeting Iron Metabolism and Ferroptosis as Novel Therapeutic Approaches in Cardiovascular Diseases

Iron functions as an essential micronutrient and participates in normal physiological and biochemical processes in the cardiovascular system. Ferroptosis is a novel type of iron-dependent cell death driven by iron accumulation and lipid peroxidation, characterized by depletion of glutathione and suppression of glutathione peroxidase 4 (GPX4). Dysregulation of iron metabolism and ferroptosis have been implicated in the occurrence and development of cardiovascular diseases (CVDs), including hypertension, atherosclerosis, pulmonary hypertension, myocardial ischemia/reperfusion injury, cardiomyopathy, and heart failure. Iron chelators deferoxamine and dexrazoxane, and lipophilic antioxidants ferrostatin-1 and liproxstatin-1 have been revealed to abolish ferroptosis and suppress lipid peroxidation in atherosclerosis, cardiomyopathy, hypertension, and other CVDs. Notably, inhibition of ferroptosis by ferrostatin-1 has been demonstrated to alleviate cardiac impairments, fibrosis and pathological remodeling during hypertension by potentiating GPX4 signaling. Administration of deferoxamine improved myocardial ischemia/reperfusion injury by inhibiting lipid peroxidation. Several novel small molecules may be effective in the treatment of ferroptosis-mediated CVDs. In this article, we summarize the regulatory roles and underlying mechanisms of iron metabolism dysregulation and ferroptosis in the occurrence and development of CVDs. Targeting iron metabolism and ferroptosis are potential therapeutic strategies in the prevention and treatment of hypertension and other CVDs.

The von Hippel-Lindau Tumor Suppressor Gene Mutations Modulate Lipocalin-2 Expression in Ferroptotic-Inflammatory Pathways

A previous study of an animal model with tumor suppressor gene von Hippel-Lindau (VHL) conditional knockdown suggested that tissue inflammation and fibrosis play important roles in the development of clear-cell renal cell carcinoma (ccRCC), which is consistent with the epidemiological evidence linking inflammatory kidney disease and renal cancer. Ferroptosis and inflammation have been linked in a recent study, but the exact mechanism remains unclear. This study is aimed at investigating the mechanism of lipocalin-2- (LCN-2-) mediated ferroptosis and inflammation in vhl-mutated HK-2 cells and mouse primary proximal tubule cells (mRTCs) and the polarization of macrophage RAW 264.7 cells. Based on the levels of lipid reactive oxygen species (ROS) and the expression of glutathione peroxidase 4 (GPX4) in HK-2 cells, we observed that a VHL mutation increased ROS production and depressed GPX4 expression, whereas LCN-2 knockdown reversed these effects. Accordingly, VHL appears to affect ferroptosis in an LCN-2-dependent manner. We also revealed that LCN-2 sensitizes HK-2 cells to inflammation and macrophage RAW 264.7 cells to M1-like polarization. This study provides novel insights into the potential therapeutic target and strategy for attenuating the progression of ccRCC by revealing the role of VHL in regulating chronic inflammation within the LCN-2-ferroptosis pathway.

Ferroptosis as a therapeutic target for inflammation-related intestinal diseases

Ferroptosis is an iron-dependent programmed cell death characterized by reactive oxygen species-induced lipid peroxidation and resultant membrane damage. Recent research has elucidated the mechanism of ferroptosis and investigated the relationship between ferroptosis and various diseases, including degenerative diseases, cancer, and inflammation. Ferroptosis is associated with inflammation-related intestinal diseases such as colitis and colitis-associated cancer. New insights into the role of ferroptosis in the pathogenesis of inflammation-related gut diseases have suggested novel therapeutic targets. In this review, we summarize current information on the molecular mechanisms of ferroptosis and describe its emerging role and therapeutic potential in inflammation-related intestinal diseases.

TP73 Isoform-specific disruption reveals a critical role of TAp73beta in growth suppression and inflammatory response

TP73 is expressed as multiple N- and C-terminal isoforms through two separate promoters or alternative splicing. While N-terminal p73 isoforms have been well studied, very little is known about p73 C-terminal isoforms. Thus, CRISPR was used to delete TP73 Exon13 (E13-KO) to induce p73α to p73β isoform switch. We showed that E13-KO led to decreased cell proliferation and migration and sensitized cells to ferroptosis, which can be reverted by knockdown of TAp73β in E13-KO cells. To understand the biological function of p73β in vivo, we generated a mouse model in that the Trp73 E13 was deleted by CRISPR. We showed that p73α to p73β isoform switch led to increased cellular senescence in mouse embryonic fibroblasts. We also showed that E13-deficient mice exhibited shorter life span and were prone to spontaneous tumors, chronic inflammation and liver steatosis as compared to WT mice. Additionally, we found that the incidence of chronic inflammation and liver steatosis was higher in E13-deficient mice than that in Trp73-deficient mice, suggesting that p73β is a strong inducer of inflammatory response. Mechanistically, we showed that TAp73β was able to induce cysteine dioxygenase 1 (CDO-1), leading to cysteine depletion and subsequently, enhanced ferroptosis and growth suppression. Conversely, knockdown of CDO-1 was able to alleviate the growth suppression and ferroptosis in E13-KO cells. Together, our data suggest that at a physiologically relevant level, TAp73β is a strong inducer of growth suppression but insufficient to compensate for loss of TAp73α in tumor suppression due to aberrant induction of inflammatory response and liver steatosis.

Establishment of a 7-gene prognostic signature based on oxidative stress genes for predicting chemotherapy resistance in pancreatic cancer

Background: Oxidative stress is involved in regulating various biological processes in human cancers. However, the effect of oxidative stress on pancreatic adenocarcinoma (PAAD) remained unclear. Methods: Pancreatic cancer expression profiles from TCGA were downloaded. Consensus ClusterPlus helped classify molecular subtypes based on PAAD prognosis-associated oxidative stress genes. Limma package filtered differentially expressed genes (DEGs) between subtypes. A multi-gene risk model was developed using Lease absolute shrinkage and selection operator (Lasso)-Cox analysis. A nomogram was built based on risk score and distinct clinical features. Results: Consistent clustering identified 3 stable molecular subtypes (C1, C2, C3) based on oxidative stress-associated genes. Particularly, C3 had the optimal prognosis with the greatest mutation frequency, activate cell cycle pathway in an immunosuppressed status. Lasso and univariate cox regression analysis selected 7 oxidative stress phenotype-associated key genes, based on which we constructed a robust prognostic risk model independent of clinicopathological features with stable predictive performance in independent datasets. High-risk group was found to be more sensitive to small molecule chemotherapeutic drugs including Gemcitabine, Cisplatin, Erlotinib and Dasatinib. The 6 of 7 genes expressions were significantly associated with methylation. Survival prediction and prognostic model was further improved through a decision tree model by combining clinicopathological features with RiskScore. Conclusion: The risk model containing seven oxidative stress-related genes may have a greater potential to assist clinical treatment decision-making and prognosis determination.

Ferroptosis triggers airway inflammation in asthma

Ferroptosis is a regulatory cell death characterized by intracellular iron accumulation and lipid peroxidation that leads to oxidative stress. Many signaling pathways such as iron metabolism, lipid metabolism, and amino acid metabolism precisely regulate the process of ferroptosis. Ferroptosis is involved in a variety of lung diseases, such as acute lung injury, chronic obstructive pulmonary disease (COPD) and pulmonary fibrosis. Increasing studies suggest that ferroptosis is involved in the development of asthma. Ferroptosis plays an important role in asthma. Iron metabolism disorders, lipid peroxidation, amino acid metabolism disorders lead to the occurrence of ferroptosis in airway epithelial cells, and then aggravate clinical symptoms in asthmatic patients. Moreover, several regulators of ferroptosis are involved in the pathogenesis of asthma, such as Nrf2, heme oxygenase-1, mevalonate pathway, and ferroptosis inhibitor protein 1. Importantly, ferroptosis inhibitors improve asthma. Thus, the pathogenesis of ferroptosis and its contribution to the pathogenesis of asthma help us better understand the occurrence and development of asthma, and provide new directions in asthma treatment. This article aimed to review the role and mechanism of ferroptosis in asthma, describing the relationship between ferroptosis and asthma based on signaling pathways and related regulatory factors. At the same time, we summarized current observations of ferroptosis in eosinophils, airway epithelial cells, and airway smooth muscle cells in asthmatic patients.

Effects of Ferroptosis on Cardiovascular Diseases

Ferroptosis is a novel form of programmed cell death characterized by the accumulation of iron-dependent lipid peroxides, which causes membrane injury. Under the catalysis of iron ions, cells deficient in glutathione peroxidase (GPX4) cannot preserve the balance in lipid oxidative metabolism, and the buildup of reactive oxygen species on the membrane lipids leads to cell death. An increasing body of evidence suggests that ferroptosis plays a significant role in the development and occurrence of cardiovascular diseases. In this paper, we mainly elaborated on the molecular mechanisms regulating ferroptosis and its impact on cardiovascular disease to lay the groundwork for future studies on the prophylaxis and treatment of this patient population.

Elabela blunts doxorubicin-induced oxidative stress and ferroptosis in rat aortic adventitial fibroblasts by activating the KLF15/GPX4 signaling

Doxorubicin (DOX) is a chemotherapeutic drug for a variety of malignancies, while its application is restricted by the cardiovascular toxic effects characterized by oxidative stress. Ferroptosis is a novel iron-dependent regulated cell death driven by lipid peroxidation. Our study aimed to investigate the role of Elabela (ELA) in DOX-induced oxidative stress and ferroptosis. In cultured rat aortic adventitial fibroblasts (AFs), stimulation with DOX dramatically induced cytotoxicity with reduced cell viability and migration ability, and enhanced lactate dehydrogenase (LDH) activity. Importantly, ELA and ferrostatin-1 (Fer-1) mitigated DOX-mediated augmentation of reactive oxygen species (ROS) in rat aortic AFs, accompanied by upregulated levels of Nrf2, SLC7A11, GPX4, and GSH. In addition, ELA reversed DOX-induced dysregulation of apoptosis- and inflammation-related factors including Bax, Bcl2, interleukin (IL)-1β, IL6, IL-10, and CXCL1. Intriguingly, knockdown of Krüppel-like factor 15 (KLF15) by siRNA abolished ELA-mediated alleviation of ROS production and inflammatory responses. More importanly, KLF15 siRNA impeded the beneficial roles of ELA in DOX-pretreated rat aortic AFs by suppressing the Nrf2/SLC7A11/GPX4 signaling. In conclusion, ELA prevents DOX-triggered promotion of cytotoxicity, and exerts anti-oxidative and anti-ferroptotic effects in rat aortic AFs via activation of the KLF15/GPX4 signaling, indicating a promising therapeutic value of ELA in antagonizing DOX-mediated cardiovascular abnormality and disorders.

CHAC1 exacerbates LPS-induced ferroptosis and apoptosis in HK-2 cells by promoting oxidative stress

BACKGROUND

Sepsis-induced acute kidney injury (AKI) is a singularly grievous and life-threatening syndrome. Its pathogenesis is closely related to inflammatory response, apoptosis, oxidative stress, and ferroptosis. Cation transport regulator-like protein 1 (CHAC1), as a proapoptic factor, may be involved in apoptosis, oxidative stress, and ferroptosis. This study aimed to explore the role of CHAC1 in the lipopolysaccharide (LPS)-induced the human renal proximal tubular epithelial (HK-2) cells.

METHODS

HK-2 cells were challenged with LPS to construct a model of sepsis-induced AKI in vitro. The role of CHAC1 in the LPS-induced HK-2 cells was explored using Western blot assay, cell counting kit-8 (CCK-8), flow cytometry, and colorimetric assays. Additionally, N-acetyl cysteine (NAC) was incubated with HK-2 cells to define deeply the relation between oxidative stress and apoptosis or ferroptosis.

RESULTS

The expression of CHAC1 was enhanced in the kidney tissues of mice with sepsis--induced multiple organ dysfunction syndrome (MODS), through the Gene Expression Omnibus database (GSE60088 microarray dataset), and in the LPS-induced HK-2 cells. The cell viability was significantly reduced by LPS treatment, which was at least partly restored by the transfection of siCHAC1#1 and siCHAC1#2 but not siNC. In addition, down-regulation of CHAC1 counteracted the LPS-induced reactive oxygen species level and malonaldehyde concentrations while restored the LPS-induced glutathione concentrations. Meanwhile, interference of CHAC1 neutralized LPS-induced apoptosis rate, and the relative level of cleaved poly(ADP-ribose) polymerase (PARP)/PARP, and cleaved caspase-3/caspase-3. In addition, silencing of CHAC1 recovered the LPS-induced enhanced protein level of glutathione peroxidase 4 (GPx4) whereas antagonized the LPS-induced relative protein level of ACSL4 and that of iron. Moreover, application of NAC inverted the effect of CHAC1 on apoptosis and ferroptosis in HK-2 cells.

CONCLUSION

CHAC1 exacerbated ferroptosis and apoptosis by enhancing oxidative stress in LPS-induced HK-2 cells.

Research progress on the role of ferroptosis in cardiovascular disease

The cardiovascular disease pathogenesis is extremely complex and seriously threatens human health. Cardiomyocyte death plays a significant role in cardiovascular disease occurrence and development. In addition to the previously revealed modes of cell death (apoptosis, autophagy, and pyroptosis), ferroptosis is highly related to the development of cardiovascular diseases, including arrhythmia, atherosclerosis, and myocardial ischemia/reperfusion. Ferroptosis is a novel cell death pathway driven by lipid peroxidation and iron overload. Lipid, amino acid, and iron metabolism regulate the ferroptosis pathway. Small molecule compounds (iron chelators, antioxidants, and ferroptosis inhibitors) and genetic programming can alleviate or prevent cardiovascular disease by inhibiting the ferroptosis pathway. Ferroptosis plays a key role in various cardiovascular disease occurrence and development, and inhibiting ferroptosis in cardiomyocytes is expected to become a feasible treatment method. In this mini-review, we systematically summarize the molecular mechanisms of ferroptosis in different cardiovascular diseases, delineate the regulatory network between ferroptosis and cardiovascular diseases, and highlight its potential therapeutic targets.

Molecular mechanisms of ferroptosis and relevance to inflammation

INTRODUCTION

Inflammation is a defensive response of the organism to irritation which is manifested by redness, swelling, heat, pain and dysfunction. The inflammatory response underlies the role of various diseases. Ferroptosis, a unique modality of cell death, driven by iron-dependent lipid peroxidation, is regulated by multifarious cellular metabolic pathways, including redox homeostasis, iron processing and metabolism of lipids, as well as various signaling pathways associated with diseases. A growing body of evidence suggests that ferroptosis is involved in inflammatory response, and targeting ferroptosis has great prospects in preventing and treating inflammatory diseases.

MATERIALS AND METHODS

Relevant literatures on ferroptosis, inflammation, inflammatory factors and inflammatory diseases published from January 1, 2010 to now were searched in PubMed database.

CONCLUSION

In this review, we summarize the regulatory mechanisms associated with ferroptosis, discuss the interaction between ferroptosis and inflammation, the role of mitochondria in inflammatory ferroptosis, and the role of targeting ferroptosis in inflammatory diseases. As more and more studies have confirmed the relationship between ferroptosis and inflammation in a wide range of organ damage and degeneration, drug induction and inhibition of ferroptosis has great potential in the treatment of immune and inflammatory diseases.

β-Caryophyllene Acts as a Ferroptosis Inhibitor to Ameliorate Experimental Colitis

Macrophage infiltration is one of the main pathological features of ulcerative colitis (UC) and ferroptosis is a type of nonapoptotic cell death, connecting oxidative stress and inflammation. However, whether ferroptosis occurs in the colon macrophages of UC mice and whether targeting macrophage ferroptosis is an effective approach for UC treatment remain unclear. The present study revealed that macrophage lipid peroxidation was observed in the colon of UC mice. Subsequently, we screened several main components of essential oil from Artemisia argyi and found that β-caryophyllene (BCP) had a good inhibitory effect on macrophage lipid peroxidation. Additionally, ferroptotic macrophages were found to increase the mRNA expression of tumor necrosis factor alpha (Tnf-α) and prostaglandin-endoperoxide synthase 2 (Ptgs2), while BCP can reverse the effects of inflammation activated by ferroptosis. Further molecular mechanism studies revealed that BCP activated the type 2 cannabinoid receptor (CB2R) to inhibit macrophage ferroptosis and its induced inflammatory response both in vivo and in vitro. Taken together, BCP potentially ameliorated experimental colitis inflammation by inhibiting macrophage ferroptosis. These results revealed that macrophage ferroptosis is a potential therapeutic target for UC and identified a novel mechanism of BCP in ameliorating experimental colitis.

Phenolic furanochromene hydrazone derivatives: Synthesis, antioxidant activity, ferroptosis inhibition, DNA cleavage and DNA molecular docking studies

Twenty-four phenolic furanochromene hydrazone derivatives were designed and synthesized in order to evaluate structure-activity relationships in a series of antioxidant-related assays. The derivatives have varying substitution patterns on the phenol ring, with some compounds having one, two or three hydroxy groups, and others containing one hydroxy group in combination with methoxy, methyl, bromo, iodo and/or nitro groups. Antioxidant activity was determined using the DPPH free radical scavenging and CUPRAC assays. Compounds containing ortho-dihydroxy and para-dihydroxy patterns had the highest free radical scavenging activity, with IC50 values ranging from 5.0 to 28 μM. Similarly, derivatives with ortho-dihydroxy and para-dihydroxy patterns, together with a 4-hydroxy-3,5‑dimethoxy pattern, displayed strong copper (II) ion reducing capacity, using Trolox as a standard. Trolox equivalent antioxidant capacity (TEAC) coefficients for these derivatives ranged from 1.75 to 3.97. As further evidence of antioxidant potential, greater than half of the derivatives reversed erastin-induced ferroptosis in HaCaT cells. In addition, twenty-three of the derivatives were effective at cleaving supercoiled plasmid DNA in the presence of copper (II) ions at 1 mM, with the 3,4‑dihydroxy derivative showing cleavage to both the linear and open circular forms at 3.9 uM. The interaction of the phenolic furanochromene derivatives with DNA was confirmed by molecular docking studies, which revealed that all the derivatives bind favorably in the minor groove of DNA.

Nrf2 Regulates Oxidative Stress and Its Role in Cerebral Ischemic Stroke

Cerebral ischemic stroke is characterized by acute ischemia in a certain part of the brain, which leads to brain cells necrosis, apoptosis, ferroptosis, pyroptosis, etc. At present, there are limited effective clinical treatments for cerebral ischemic stroke, and the recovery of cerebral blood circulation will lead to cerebral ischemia-reperfusion injury (CIRI). Cerebral ischemic stroke involves many pathological processes such as oxidative stress, inflammation, and mitochondrial dysfunction. Nuclear factor erythroid 2-related factor 2 (Nrf2), as one of the most critical antioxidant transcription factors in cells, can coordinate various cytoprotective factors to inhibit oxidative stress. Targeting Nrf2 is considered as a potential strategy to prevent and treat cerebral ischemia injury. During cerebral ischemia, Nrf2 participates in signaling pathways such as Keap1, PI3K/AKT, MAPK, NF-κB, and HO-1, and then alleviates cerebral ischemia injury or CIRI by inhibiting oxidative stress, anti-inflammation, maintaining mitochondrial homeostasis, protecting the blood-brain barrier, and inhibiting ferroptosis. In this review, we have discussed the structure of Nrf2, the mechanisms of Nrf2 in cerebral ischemic stroke, the related research on the treatment of cerebral ischemia through the Nrf2 signaling pathway in recent years, and expounded the important role and future potential of the Nrf2 pathway in cerebral ischemic stroke.

Functional analysis of differently expressed ferroptosis-related genes in patients with mitral valve prolapse

Background: The prevalence of mitral valve prolapse (MVP) in heart valvular diseases is globally increasing. However, the understanding of its etiology and pathogenesis is limited. So far, the relationship between ferroptosis-related genes and long non-coding RNAs (lncRNAs) in MVP remains unexplored. This study investigates the potential pathogenesis of ferroptosis-related genes in MVP and provides a therapeutic target for the disease.

Methods: Blood samples from patients with MVP and healthy volunteers were collected for transcriptomic sequencing to analyze the expression of ferroptosis-related differentially expressed genes (DEGs) and differentially expressed long non-coding RNAs (DElncRNAs Co-expression network of ferroptosis-related DEGs and DElncRNAs. Furthermore, this work conducted GO and KEGG enrichment analyses.

Results:CDKN2A, SLC1A4, ATF3, and other core genes related to the mitral valve prolapse were screened out. CDKN2A, SLC1A4, and ATF3 genes were at the core position of the network, regulated by numerous lncRNAs. Notably, these genes are primarily involved in the extracellular region and p53 signaling pathway.

Conclusion: In summary, CDKN2A, SLC1A4, and ATF3 regulate the pathophysiological process of MVP and are potential therapeutic targets.

Cadmium induces ferroptosis mediated inflammation by activating Gpx4/Ager/p65 axis in pancreatic β-cells

Cadmium (Cd) is a widely distributed endocrine disruptor and has been reported to be closely correlated to the pathogenesis of diabetes. Since pancreatic β-cells loss and dysfunction are central to pathogenesis of diabetes, studying Cd toxicity on pancreatic β-cells and its molecular mechanism is an important scientific issue. However, less attention has been payed to study how Cd induces pancreatic β-cells death and dysfunction in recent years. Thus, our study aims to explore the toxic mechanism of Cd treatment on pancreatic β-cells using both cellular and animal models. Firstly, it was confirmed that Cd induced decreased cell viability and insulin secretion in a dose-and time-dependent manner in MIN6 cells. To explore the underlying mechanism, transcriptomic analysis was employed to screen the differentially expressed genes and disturbed metabolic pathways. Go and KEGG analysis showed that Cd exposure triggered ferroptosis process in MIN6 cells. We further validated that Cd led to GSH depletion, Gpx4 reduction, lipid peroxidation, mitochondrial membrane potential loss and ultrastructural damage at mitochondrial level. Since immune system process was also perturbed based on GO analysis, we found that Cd activated Ager/Pkc/p65 inflammatory process. Moreover, ferroptosis inhibitor Fer-1 could effectively antagonized the activation of Ager-mediated immune process. It was also revealed that Cd induced iron accumulation as well as decreased Gpx4 expression in mice islets. We also uncovered that Cd led to systemic and pancreatic inflammation as early as third week after Cd exposure. Our study emphasizes the importance of ferroptotic cell death on Cd-induced systemic chronic inflammation. A novel target is provided to prevent Cd-induced pancreatic β-cells dysfunction and improve the chronic inflammatory state for prediabetes prevention.

Integrated Bioinformatics-Based Identification of Ferroptosis-Related Genes in Carotid Atherosclerosis

Background. Ferroptosis, a type of cell death caused by phospholipid peroxidation, has lately been linked to the onset and development of numerous illnesses. Numerous investigations have demonstrated the close relationship between lipid peroxidation and carotid atherosclerosis. In order to get new knowledge for targeted therapy, bioinformatics analysis was employed in this study to discover the probable ferroptosis-related genes of carotid atherosclerosis. Methods. The GSE43292 gene expression dataset was downloaded from the Gene Expression Omnibus (GEO) database. The differentially expressed ferroptosis-related genes were screened by R software and then analyzed by protein-protein interaction (PPI) network, differential gene correlation analysis, Kyoto Encyclopedia of Gene and Genome (KEGG) pathway, and Gene Ontology (GO) terminology enrichment analysis to explore the functional role. Result. In samples of atherosclerosis, we found 33 ferroptosis genes that were differentially expressed, including 21 upregulated genes and 12 downregulated genes. These differentially elevated genes were mainly connected to the ferroptosis and glutathione metabolism pathways, according to GO and KEGG enrichment analysis. We also discovered 10 hub genes and 2 important modules through the analysis of the PPI network and the creation of key modules. Conclusion. The current findings imply that the carotid atherosclerosis phenomenon involves ferroptosis, and 10 important genes associated to ferroptosis may play a role in the development of carotid atherosclerosis. This study offered a novel approach to future research on the carotid atherosclerosis pathogenic processes and treatment targets.

Mapping current research and identifying hotspots of ferroptosis in cardiovascular diseases

OBJECTIVE

Ferroptosis is a unique cell death depended on iron metabolism disorder which is different from previous apoptosis-regulated cell death. Early studies have proposed that ferroptosis is closely associated with multiple cardiovascular diseases (CVDs). However, the relationship of ferroptosis and CVDs has not been summarized by using bibliometric analysis. We intended to illustrate the development of ferroptosis in CVDs over the past years and provide relevant valuable information.

MATERIALS AND METHODS

The authoritative database of Web of Science Core Collection was collected for retrieving ferroptosis studies in CVDs. In this work, statistical and visualization analysis were conducted using VOSviewer and Citespace.

RESULTS

A total of 263 studies were included in the final study. From the perspective of the overall literature, the study maintains an increased trend year by year and most manuscripts belonged to original article. China was the most productive country with the utmost scientific research output, as well as the institutions and authors, followed by Germany and the United States of America (USA). Jun Peng from China contributes to the most publications. Collaborative efforts between institutes and authors were limited and there was little widespread cooperation. In addition, burst keywords analysis discovered that ischemia-reperfusion (I/R) injury, heart failure (HF), and atherosclerosis were the top three research directions of ferroptosis in CVDs. The burst investigation and timeline views also indicated that endothelial injury and gut microbiota may also serve as new research topics in the future.

CONCLUSION

This study provided comprehensive and specific information about the most influential articles on ferroptosis in CVDs. The relationship between ferroptosis and CVDs had attracted the scholar's concerns especially in China. Cooperations and communications between countries and institutions should be emphasized and future directions can be concentrated on endothelial disorder and gut microbiota.

Aggravated Gut Microbiota and Metabolomic Imbalances Are Associated with Hypertension Patients Comorbid with Atrial Fibrillation

Disordered gut microbiota (GM) as the co-contributor of atrial fibrillation (AF) and hypertension (HTN) might be associated with AF risk in HTN. This study aimed to explore the altered GM community and metabolic patterns between 27 HTN patients with AF (HTN-AF) and 27 non-AF HTN patients through fecal metagenomic and serum metabolomic analysis. Compared to non-AF HTN patients, significant microbial alterations (p = 0.004), including increased microbial diversity (p < 0.05), shifted enterotype dominated by Prevotella to Bacteroides, and abundant disease-linked genera Ruminococcus, Streptococcus, Veillonella, Dorea, and Enterococcus, were observed in HTN-AF patients. A species-based random forest prediction model was associated with the risk of AF occurrence in HTN patients. Furthermore, GM metabolic profiles dramatically differed between HTN and HTN-AF patients, especially the imbalance of saturated and unsaturated fatty acids. In HTN-AF patients, circulating palmitic acid and arachidonic acid levels were significantly elevated, while the levels of tetracosahexaenoic acid, oleic acid, linoleic acid, and stearic acid were decreased (p < 0.001, VIP > 1), mediating 85.99% of gut microbial indirect effects on AF (p < 0.001). Thus, our findings preliminarily indicated that exacerbated dysbiosis of GM and relevant metabolites was associated with high AF susceptibility and might be a potential target for AF prediction and prevention in HTN.

Identification of cross-talk pathways and ferroptosis-related genes in periodontitis and type 2 diabetes mellitus by bioinformatics analysis and experimental validation

Purpose

There is a bidirectional relationship between periodontitis and type 2 diabetes mellitus (T2DM). The aim of this study was to further explore the pathogenesis of this comorbidity, screen out ferroptosis-related genes involved in the pathological process, and predict potential drug targets to develop new therapeutic strategies.

Methods

Common cross-talk genes were identified from periodontitis datasets (GSE16134, GSE10334 and GSE106090) and T2DM databases (DisGeNET and GeneCard). Then, GO and KEGG enrichment analyses, PPI network analysis and hub gene identification were performed. The association between ferroptosis and periodontitis with T2DM was investigated by Pearson correlation analysis. Core ferroptosis-related cross-talk genes were identified and verified by qRT-PCR. Potential drugs targeting these core genes were predicted via DGIDB.

Results

In total, 67 cross-talk genes and two main signalling pathways (immuno-inflammatory pathway and AGE-RAGE signalling pathway) were identified. Pearson correlation analysis indicated that ferroptosis served as a crucial target in the pathological mechanism and treatment of periodontitis with T2DM. IL-1β, IL-6, NFE2L2 and ALOX5 were identified as core ferroptosis-related genes and the qRT-PCR detection results were statistically different. In total, 13 potential drugs were screened out, among which, Echinacea and Ibudilast should be developed first.

Conclusions

This study contributes to a deeper understanding of the common pathogenesis of periodontitis and T2DM and provides new insights into the role of ferroptosis in this comorbidity. In addition, two drugs with potential clinical application value were identified. The potential utility of these drugs requires further experimental investigation.

IDH1 Promotes Foam Cell Formation by Aggravating Macrophage Ferroptosis

Simple Summary

In our study, the involvement of IDH1 in atherosclerotic foam cells was explored. Inhibiting macrophage ferroptosis and foam cell formation by knocking down IDH1 is a promising study direction for better understanding the occurrence and progression of atherosclerosis, as well as the treatment targets for atherosclerosis.

Abstract

A distinctive feature of ferroptosis is intracellular iron accumulation and the impairment of antioxidant capacity, resulting in a lethal accumulation of lipid peroxides leading to cell death. This study was conducted to determine whether inhibiting isocitrate dehydrogenase 1 (IDH1) may help to prevent foam cell formation by reducing oxidized low-density lipoprotein (ox-LDL)-induced ferroptosis in macrophages and activating nuclear factor erythroid 2-related factor 2 (NRF2). Gene expression profiling (GSE70126 and GSE70619) revealed 21 significantly different genes, and subsequent bioinformatics research revealed that ferroptosis and IDH1 play essential roles in foam cell production. We also confirmed that ox-LDL elevates macrophage ferroptosis and IDH1 protein levels considerably as compared with controls. Ferrostatin-1 (Fer-1), a ferroptosis inhibitor, reduced ox-LDL-induced elevated Fe²⁺ levels, lipid peroxidation (LPO) buildup, lactate dehydrogenase (LDH) buildup, glutathione (GSH) depletion, glutathione peroxidase 4 (GPX4), ferritin heavy polypeptide 1 (FTH1), and solute carrier family 7 member 11 (SLC7A11) protein downregulation. More crucially, inhibiting IDH1 reduced Fe²⁺ overload, lipid peroxidation, LDH, and glutathione depletion, and elevated GPX4, FTH1, and SLC7A11 protein expression, resulting in a reduction in ox-LDL-induced macrophage ferroptosis. IDH1 inhibition suppressed ox-LDL-induced macrophage damage and apoptosis while raising NRF2 protein levels. We have demonstrated that inhibiting IDH1 reduces ox-LDL-induced ferroptosis and foam cell formation in macrophages, implying that IDH1 may be an important molecule regulating foam cell formation and may be a promising molecular target for the treatment of atherosclerosis.

Emerging roles of ferroptosis in cardiovascular diseases

The mechanism of cardiovascular diseases (CVDs) is complex and threatens human health. Cardiomyocyte death is an important participant in the pathophysiological basis of CVDs. Ferroptosis is a new type of iron-dependent programmed cell death caused by excessive accumulation of iron-dependent lipid peroxides and reactive oxygen species (ROS) and abnormal iron metabolism. Ferroptosis differs from other known cell death pathways, such as apoptosis, necrosis, necroptosis, autophagy and pyroptosis. Several compounds have been shown to induce or inhibit ferroptosis by regulating related key factors or signalling pathways. Recent studies have confirmed that ferroptosis is associated with the development of diverse CVDs and may be a potential therapeutic drug target for CVDs. In this review, we summarize the characteristics and related mechanisms of ferroptosis and focus on its role in CVDs, with the goal of inspiring novel treatment strategies.

Senegenin Rescues PC12 Cells with Oxidative Damage Through Inhibition of Ferroptosis

Oxidative stress is one of the pathological mechanisms of Alzheimer's disease (AD), and ferroptosis has been determined to be involved in neurodegenerative diseases such as AD. Senegenin (Sen) prevents oxidative damage in nerve cells via a mechanism that may be highly related to ferroptosis. However, the mechanism of ferroptosis pathway involvement in AD is unclear. In this study, we established a model of PC12 cytotoxic injury induced by Aβ_25-35, and we detected the level of oxidative damage, MMP, and ferroptosis-related protein expression. The results showed that, compared with control group, the level of ROS increased, GPX activities decreased, and MDA levels increased in Aβ_25-35 group. Aβ_25-35 could induce mitochondrial depolarization in PC12 cells and Fer-1 could not reverse this damage. WB revealed that Aβ_25-35 group had increased ACSL4 and PEBP1 proteins, and decreased GPX4 protein. After adding Sen in the model, the level of oxidative damage was reduced, and mitochondrial depolarization was reversed compared with Aβ_25-35 group. WB suggested that the expression of ACSL4 and PEBP1 proteins decreased, and the expression of GPX4 protein increased by Sen treatment. In conclusion, we found that Sen exhibits strong neuroprotective activity against Aβ_25-35 induced oxidative damage and lipid metabolic associated with ferroptosis. Inhibiting nerve cell ferroptosis might facilitate the future development of strategies to AD.

Ether lipid deficiency disrupts lipid homeostasis leading to ferroptosis sensitivity

Ferroptosis is an iron-dependent form of regulated cell death associated with uncontrolled membrane lipid peroxidation and destruction. Previously, we showed that dietary dihomo-gamma-linolenic acid (DGLA; 20: 3(n-6)) triggers ferroptosis in the germ cells of the model organism, Caenorhabditis elegans. We also demonstrated that ether lipid-deficient mutant strains are sensitive to DGLA-induced ferroptosis, suggesting a protective role for ether lipids. The vinyl ether bond unique to plasmalogen lipids has been hypothesized to function as an antioxidant, but this has not been tested in animal models. In this study, we used C. elegans mutants to test the hypothesis that the vinyl ether bond in plasmalogens acts as an antioxidant to protect against germ cell ferroptosis as well as to protect from whole-body tert-butyl hydroperoxide (TBHP)-induced oxidative stress. We found no role for plasmalogens in either process. Instead, we demonstrate that ether lipid-deficiency disrupts lipid homeostasis in C. elegans, leading to altered ratios of saturated and monounsaturated fatty acid (MUFA) content in cellular membranes. We demonstrate that ferroptosis sensitivity in both wild type and ether-lipid deficient mutants can be rescued in several ways that change the relative abundance of saturated fats, MUFAs and specific polyunsaturated fatty acids (PUFAs). Specifically, we reduced ferroptosis sensitivity by (1) using mutant strains unable to synthesize DGLA, (2) using a strain carrying a gain-of-function mutation in the transcriptional mediator MDT-15, or (3) by dietary supplementation of MUFAs. Furthermore, our studies reveal important differences in how dietary lipids influence germ cell ferroptosis versus whole-body peroxide-induced oxidative stress. These studies highlight a potentially beneficial role for endogenous and dietary MUFAs in the prevention of ferroptosis.

Metabolic heterogeneity protects metastatic mucosal melanomas cells from ferroptosis

Cancer heterogeneity has been proposed to be one of the main causes of metastatic dissemination and therapy failure. However, the underlying mechanisms of this phenomenon remain poorly understood. Melanoma is an aggressive malignancy with a high heterogeneity and metastatic potential. Therefore, the present study investigated the possible association between cancer heterogeneity and metastasis in melanoma. In total, two novel Chinese oral mucosal melanoma (COMM) cell lines, namely COMM-1 and COMM-2, were established for exploring methods into preventing the loss of cellular heterogeneity caused by long-term cell culture. Each cell line was grown under two different models of culture, which yielded two subtypes, one exhibited an adhesive morphology (COMM-AD), whereas the other was grown in suspension (COMM-SUS). Compared with the COMM-AD cells, the COMM-SUS cells exhibited higher metastatic capacities and autofluorescence. Further investigations indicated that the COMM-SUS cells exhibited metabolic reprogramming by taking up lactate produced by COMM-AD cells at increased levels to accumulate NADH through monocarboxylate transporter 1, whilst also increasing NADPH levels through the pentose phosphate pathway (PPP). Additionally, increased NADH and NADPH levels in the COMM-SUS cells, coupled with the upregulation of the anti-ferroptotic proteins, glutathione peroxidase 4 and ferroptosis suppressor protein 1, enabled them to resist ferroptotic cell death induced by oxidative stress during hematogenous dissemination. The inhibition of ferroptosis was found to substantially increase the metastatic capacity of COMM-AD cells. Furthermore, suppressing lactate uptake and impairing PPP activation significantly decreased the metastatic potential of the COMM-SUS cells. Thus, the present study on metabolic heterogeneity in COMM cells potentially provides a novel perspective for exploring this mechanism underlying cancer metastasis.

Serum ferritin as a crucial biomarker in the diagnosis and prognosis of intravenous immunoglobulin resistance and coronary artery lesions in Kawasaki disease: A systematic review and meta-analysis

Background

Early identification and treatment are paramount for intravenous immunoglobulin (IVIG) resistance and coronary artery lesions (CALs) in patients with Kawasaki disease (KD). Unfortunately, there is no single crucial biomarker to identify these patients in a timely manner, which makes KD the most common cause of acquired heart disease in children in developed countries. Recently, many studies have focused on the association between serum ferritin (SF), IVIG resistance, and CALs in KD. We thus performed a systematic review and meta-analysis to ascertain the diagnostic and prognostic values of SF in predicting IVIG resistance and CALs in KD in the acute phase.

Methods

The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the receiver operating characteristic curve (AUC) were extracted from the data to evaluate the SF levels in KD. The hazard ratios (HRs) of related risk factors and their corresponding 95% confidence intervals (CIs) were applied to compute the pooled assessments of the outcomes.

Results

A total of 11 eligible articles were included in this meta-analysis, including twenty studies for diagnosis and five studies for prognosis. In terms of diagnostic values, SF could identify KD patients in the overall studies with a relatively high pooled sensitivity, specificity, PLR, NLR, DOR, and AUC of 0.76 (95% CI: 0.69-0.82), 0.82 (95% CI: 0.76-0.88), 4.33 (95% CI: 3.07-6.11), 0.29 (95% CI: 0.22-0.38), 15.0 (95% CI: 9.00-25.00), and 0.86 (95% CI: 0.83-0.89), respectively. In studies comparing KD patients and controls, there were a relatively high pooled sensitivity, specificity, PLR, NLR, DOR, and AUC of 0.79 (95% CI: 0.72-0.84), 0.84 (95% CI: 0.79-0.91), 4.61 (95% CI: 3.27-6.51), 0.26 (95% CI: 0.20-0.34), 20.82 (95% CI: 11.83-36.64), and 0.89 (95% CI: 0.86-0.91), respectively. For the prognostic values, we found poor survival outcomes based on KD patients (HR = 1.31, 95% CI: 1.07-1.59, P = 0.008).

Conclusion

Our meta-analysis suggests that SF may be used as a workable and critical biomarker for the diagnosis and prognosis of IVIG resistance and CALs in patients with KD. We also propose that maintaining the dynamic balance between iron, SF, and ferroptosis will be an important therapeutic strategy to reduce the morbidity of CALs.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/], identifier [CRD42022279157].

Key ferroptosis-related genes in abdominal aortic aneurysm formation and rupture as determined by combining bioinformatics techniques

Objectives

Abdominal aortic aneurysm (AAA) is a cardiovascular disease with high mortality and pathogenesis closely related to various cell death types, e.g., autophagy, apoptosis and pyroptosis. However, the association between AAA and ferroptosis is unknown.

Methods

GSE57691 and GSE98278 dataset were obtained from the Gene Expression Omnibus database, and a ferroptosis-related gene (FRG) set was downloaded from the FerrDb database. These data were normalized, and ferroptosis-related differentially expressed genes (FDEGs, AAA vs. normal samples) were identified using the limma package in R. FRGs expression was analyzed by Gene Set Expression Analysis (GSEA), and FDEGs were analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes (KEGG) pathway enrichment analyses using the clusterProfiler package in R and ClueGO in Cytoscape. Protein–protein interaction networks were assembled using Cytoscape, and crucial FDEGs were identified using CytoHubba. Critical FDEG transcription factors (TFs) were predicted with iRegulon. FDEGs were verified in GSE98278 set, and key FDEGs in AAA (compared with normal samples) and ruptured AAA (RAAA; compared with AAA samples) were identified. Ferroptosis-related immune cell infiltration and correlations with key genes were analyzed by CIBERSORT. Key FEDGs were reverified in Ang II-induced AAA models of ApoE^–/– and CD57B/6J mice by immunofluorescence assay.

Results

In AAA and normal samples, 40 FDEGs were identified, and the expression of suppressive FRGs was significantly downregulated with GSEA. For FDEGs, the GO terms were response to oxidative stress and cellular response to external stimulus, and the KEGG pathways were the TNF and NOD-like receptor signaling pathways. IL6, ALB, CAV1, PTGS2, NOX4, PRDX6, GPX4, HSPA5, HSPB1, and NCF2 were the most enriched genes in the crucial gene cluster. CEBPG, NFAT5, SOX10, GTF2IRD1, STAT1, and RELA were potential TFs affecting these crucial genes. Ferroptosis-related immune cells involved in AAA formation were CD8+ T, naive CD4+ T, and regulatory T cells (Tregs); M0 and M2 macrophages; and eosinophils. Tregs were also involved in RAAA. GPX4, SLC2A1, and PEBP1 expression was downregulated in both the RAAA and AAA samples. GPX4 and PEBP1 were more important in AAA because they influenced ferroptosis-related immune cell infiltration, and SLC2A1 was more important in RAAA.

Conclusions

This is the first study to show that ferroptosis is crucial to AAA/RAAA formation. The TNF and NOD-like signaling pathways and ferroptosis-related immune cell infiltration play key roles in AAA/RAAA. GPX4 is a key ferroptosis-related gene in AAA. Ferroptosis and related genes might be promising targets in the treatment of AAA/RAAA.

Unraveling the interplay between iron homeostasis, ferroptosis and extramedullary hematopoiesis

Iron participates in myriad processes necessary to sustain life. During the past decades, great efforts have been made to understand iron regulation and function in health and disease. Indeed, iron is associated with both physiological (e.g., immune cell biology and function and hematopoiesis) and pathological (e.g., inflammatory and infectious diseases, ferroptosis and ferritinophagy) processes, yet few studies have addressed the potential functional link between iron, the aforementioned processes and extramedullary hematopoiesis, despite the obvious benefits that this could bring to clinical practice. Further investigation in this direction will shape the future development of individualized treatments for iron-linked diseases and chronic inflammatory disorders, including extramedullary hematopoiesis, metabolic syndrome, cardiovascular diseases and cancer.

Cardiomyocyte death in sepsis: Mechanisms and regulation (Review)

Sepsis‑induced cardiac dysfunction is one of the most common types of organ dysfunction in sepsis; its pathogenesis is highly complex and not yet fully understood. Cardiomyocytes serve a key role in the pathophysiology of cardiac function; due to the limited ability of cardiomyocytes to regenerate, their loss contributes to decreased cardiac function. The activation of inflammatory signalling pathways affects cardiomyocyte function and modes of cardiomyocyte death in sepsis. Prevention of cardiomyocyte death is an important therapeutic strategy for sepsis‑induced cardiac dysfunction. Thus, understanding the signalling pathways that activate cardiomyocyte death and cross‑regulation between death modes are key to finding therapeutic targets. The present review focused on advances in understanding of sepsis‑induced cardiomyocyte death pathways, including apoptosis, necroptosis, mitochondria‑mediated necrosis, pyroptosis, ferroptosis and autophagy. The present review summarizes the effect of inflammatory activation on cardiomyocyte death mechanisms, the diversity of regulatory mechanisms and cross‑regulation between death modes and the effect on cardiac function in sepsis to provide a theoretical basis for treatment of sepsis‑induced cardiac dysfunction.

Counteraction of Myocardial Ferritin Heavy Chain Deficiency by Heme Oxygenase-1

Given the abundance of heme proteins (cytochromes) in the mitochondrion, it is evident that a meticulously orchestrated iron metabolism is essential for cardiac health. Here, we examined the functional significance of myocardial ferritin heavy chain (FtH) in a model of acute myocardial infarction. We report that FtH deletion did not alter either the mitochondrial regulatory and surveillance pathways (fission and fusion) or mitochondrial bioenergetics in response to injury. Furthermore, deletion of myocardial FtH did not affect cardiac function, assessed by measurement of left ventricular ejection fraction, on days 1, 7, and 21 post injury. To identify the modulated pathways providing cardiomyocyte protection coincident with FtH deletion, we performed unbiased transcriptomic analysis. We found that following injury, FtH deletion was associated with upregulation of several genes with anti-ferroptotic properties, including heme oxygenase-1 (HO-1) and the cystine/glutamate anti-porter (Slc7a11). These results suggested that HO-1 overexpression mitigates ferroptosis via upregulation of Slc7a11. Indeed, using transgenic mice with HO-1 overexpression, we demonstrate that overexpressed HO-1 is coupled with increased Slc7a11 expression. In conclusion, we demonstrate that following injury, myocardial FtH deletion leads to a compensatory upregulation in a number of anti-ferroptotic genes, including HO-1. Such HO-1 induction leads to overexpression of Slc7a11 and protects the heart against ischemia-reperfusion-mediated ferroptosis, preserves mitochondrial function, and overall function of the myocardium.

Expression of antioxidant enzymes in lesions of multiple sclerosis and its models

Oxidative stress promotes tissue injury in the central nervous system in neurological disorders such as multiple sclerosis (MS). To protect against this, antioxidant enzymes including superoxide dismutase-1 (SOD1), heme oxygenase-1 (HO-1), peroxiredoxin-5 (PRDX5) and glutathione peroxidase-4 (GPX4) may be upregulated. However, whether antioxidant enzyme elevation in mouse models of neurodegeneration corresponds to their expression in human diseases such as MS requires investigation. Here, we analyzed and compared the expression of SOD1, HO-1, PRDX5 and GPX4 in the murine spinal cord of three models of MS: focal lesions induced by (1) oxidized phosphatidylcholine or (2) lysophosphatidylcholine (lysolecithin), and (3) diffuse lesions of experimental autoimmune encephalomyelitis. Notably, CD68⁺ microglia/macrophages were the predominant cellular populations that expressed the highest levels of the detected antioxidant enzymes. Overall, the expression patterns of antioxidant enzymes across the models were similar. The increase of these antioxidant enzymes was corroborated in MS brain tissue using spatial RNA sequencing. Collectively, these results show that antioxidant capacity is relatively conserved between mouse models and MS lesions, and suggest a need to investigate whether the antioxidant elevation in microglia/macrophages is a protective response during oxidative injury, neurodegeneration, and MS.