Novel Diagnostic Biomarkers Related to Oxidative Stress and Macrophage Ferroptosis in Atherosclerosis

Identification and experimental validation of KMO as a critical immune-associated mitochondrial gene in unstable atherosclerotic plaque

BACKGROUND

The heightened risk of cardiovascular and cerebrovascular events is associated with the increased instability of atherosclerotic plaques. However, the lack of effective diagnostic biomarkers has impeded the assessment of plaque instability currently. This study was aimed to investigate and identify hub genes associated with unstable plaques through the integration of various bioinformatics tools, providing novel insights into the detection and treatment of this condition.

METHODS

Weighted Gene Co-expression Network Analysis (WGCNA) combined with two machine learning methods were used to identify hub genes strongly associated with plaque instability. The cell-type identification by estimating relative subsets of RNA transcripts (CIBERSORT) method was utilized to assess immune cell infiltration patterns in atherosclerosis patients. Additionally, Gene Set Variation Analysis (GSVA) was conducted to investigate the potential biological functions, pathways, and mechanisms of hub genes associated with unstable plaques. To further validate the diagnostic efficiency and expression of the hub genes, immunohistochemistry (IHC), quantitative real-time polymerase chain reaction (RT-qPCR), and enzyme-linked immunosorbent assay (ELISA) were performed on collected human carotid plaque and blood samples. Immunofluorescence co-staining was also utilized to confirm the association between hub genes and immune cells, as well as their colocalization with mitochondria.

RESULTS

The CIBERSORT analysis demonstrated a significant decrease in the infiltration of CD8 T cells and an obvious increase in the infiltration of M0 macrophages in patients with atherosclerosis. Subsequently, two highly relevant modules (blue and green) strongly associated with atherosclerotic plaque instability were identified. Through intersection with mitochondria-related genes, 50 crucial genes were identified. Further analysis employing least absolute shrinkage and selection operator (LASSO) logistic regression and support vector machine recursive feature elimination (SVM-RFE) algorithms revealed six hub genes significantly associated with plaque instability. Among them, NT5DC3, ACADL, SLC25A4, ALDH1B1, and MAOB exhibited positive correlations with CD8 T cells and negative correlations with M0 macrophages, while kynurenine 3-monooxygenas (KMO) demonstrated a positive correlation with M0 macrophages and a negative correlation with CD8 T cells. IHC and RT-qPCR analyses of human carotid plaque samples, as well as ELISA analyses of blood samples, revealed significant upregulation of KMO and MAOB expression, along with decreased ALDH1B1 expression, in both stable and unstable samples compared to the control samples. However, among the three key genes mentioned above, only KMO showed a significant increase in expression in unstable plaque samples compared to stable plaque samples. Furthermore, the expression patterns of KMO in human carotid unstable plaque tissues and cultured mouse macrophage cell lines were assessed using immunofluorescence co-staining techniques. Finally, lentivirus-mediated KMO silencing was successfully transduced into the aortas of high-fat-fed ApoE-/- mice, with results indicating that KMO silencing attenuated plaque formation and promoted plaque stability in ApoE-/- mice.

CONCLUSIONS

The results suggest that KMO, a mitochondria-targeted gene associated with macrophage cells, holds promise as a valuable diagnostic biomarker for assessing the instability of atherosclerotic plaques.

Unveiling shared biomarkers and therapeutic targets between systemic lupus erythematosus and heart failure through bioinformatics analysis

Background

Systemic lupus erythematosus (SLE) is frequently accompanied by various complications, with cardiovascular diseases being particularly concerning due to their high mortality rate. Although there is clinical evidence suggesting a potential correlation between SLE and heart failure (HF), the underlying shared mechanism is not fully understood. Therefore, it is imperative to explore the potential mechanisms and shared therapeutic targets between SLE and HF.

Methods

The SLE and HF datasets were downloaded from the NCBI Gene Expression Omnibus database. Differentially expressed genes (DEGs) in both SLE and HF were performed using "limma" R package. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genes (KEGG) analyses were conducted to analyze the enriched functions and pathways of DEGs in both SLE and HF datasets. Protein-Protein Interaction network (PPI) and the molecular complex detection (MCODE) plugins in the Cytoscape software were performed to identify the shared hub genes between SLE and HF datasets. R package "limma" was utilized to validate the expression of hub genes based on SLE (GSE122459) and HF (GSE196656) datasets. CIBERSORT algorithm was utilized to analyze the immune cell infiltration of SLE and HF samples based on SLE (GSE112087) and HF (GSE116250) datasets. A weighted gene co-expression network analysis (WGCNA) network was established to further validate the hub genes based on HF dataset (GSE116250). Molecular biology techniques were conducted to validate the hub genes.

Results

999 shared DGEs were identified between SLE and HF datasets, which were mainly enriched in pathways related to Th17 cell differentiation. 5 shared hub genes among the common DGEs between SLE and HF datasets were screened and validated, including HSP90AB1, NEDD8, RPLP0, UBB, and UBC. Additionally, 5 hub genes were identified in the central part of the MEbrown module, showing the strongest correlation with dilated cardiomyopathy. HSP90AB1 and UBC were upregulated in failing hearts compared to non-failing hearts, while UBB, NEDD8, and RPLP0 did not show significant changes.

Conclusion

HSP90AB1 and UBC are closely related to the co-pathogenesis of SLE and HF mediated by immune cell infiltration. They serve as promising molecular markers and potential therapeutic targets for the treatment of SLE combined with HF.

Hederagenin protects against myocardial ischemia-reperfusion injury via attenuating ALOX5-mediated ferroptosis

Hederagenin (HDG), a medical herb, is known for its beneficial activities against diverse diseases. The cardioprotective effect of HDG has been preliminarily disclosed, but the efficacy and underlying mechanism by which HDG protects against myocardial ischemia-reperfusion (MI/R) injury have not been elucidated yet. To simulate MI/R injury, the left anterior descending artery was occluded for 30 min and then reperfusion for 120 min in a rat model, and the cellular model of hypoxia-reoxygenation (H/R) injury was constructed in H9c2 cardiomyocytes. Hematoxylin-eosin, Prussian blue, and 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) staining were conducted to assess the histological injury, iron deposition, and myocardial infarction. Myocardial enzymes and oxidative stress-related factors were detected using their commercial kits. Lipid peroxidation was measured using BODIPY581/591 probe, and iron content was detected. Cell counting kit (CCK)-8, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL), and flow cytometry assays were performed to assess cell viability and apoptosis. Protein levels were investigated by western blot. The interaction between HDG and 5-lipoxygenase (ALOX5) was verified using molecular docking. Our findings indicated that HDG significantly attenuated myocardial dysfunction by reducing infarction and myocardial injury. HDG significantly attenuated myocardial apoptosis in vitro and in vivo, as well as alleviating oxidative stress via reducing reactive oxygen species (ROS) and maintaining the balance between antioxidant and oxidant enzymes. Meanwhile, HDG inhibited I/R-induced ferroptosis in myocardium and cardiomyocytes, including reducing lipid peroxidation and iron level. Moreover, the binding relationship between HDG and ALOX5 was verified, and HDG could concentration dependently downregulate ALOX5. Furthermore, ALOX5 overexpression eliminated the inhibition of HDG on H/R-induced apoptosis, oxidative stress, and ferroptosis in H9c2 cardiomyocytes. HDG ameliorated myocardial dysfunction and cardiomyocyte injury by reducing apoptosis, oxidative stress, and ferroptosis through inhibiting ALOX5, providing a new perspective on the prevention and treatment of MI/R injury.

Increased Expression of CD74 in Atherosclerosis Associated with Inflammatory Responses of Endothelial Cells and Macrophages

To clarify the relationship between CD74 and atherosclerosis (AS) and the mechanisms in oxidized LDL (ox-LDL)-induced endothelial cell and macrophage injury. Datasets obtained from the Gene Expression Omnibus database are integrated. Differentially expressed genes (DEGs) were obtained using R software. Weighted gene co-expression network analysis (WGCNA) was performed to screen the target genes. The endothelial cell injury model and macrophage foaming model were established using ox-LDL, and CD74 expression was detected by Quantitative reverse transcription PCR (RT-qPCR) and Western blot (WB). Then, after silencing CD74, cell viability and ROS production were measured, and WB detected the expression of p-p38 MAPK and NF-κB. There were 268 DEGs associated with AS, of which CD74 was up-regulated. The turquoise module containing CD74 in WGCNA was positively associated with AS. Cell viability was significantly decreased in the endothelial cell injury and macrophage foaming models, while CD74, ROS production, NF-κB, and p-p38MAPK expression increased (P < 0.05). After silencing CD74, ROS production, NF-κB, and p-p38MAPK expression were decreased and cell viability was higher than the model group (P < 0.05). CD74 is up-regulated in endothelial cell injury and macrophage foaming models and is involved in AS progression via the NF-κB and MAPK signaling pathways.

Visualization of the Ferroptosis in Atherosclerotic Plaques with Nanoprobe Engineered by Macrophage Cell Membranes

Atherosclerosis (AS) is the root cause of cardiovascular diseases. Ferroptosis is characterized by highly iron-dependent lipid peroxidation and has been reported to play an important role in the pathogenesis of AS. Visualization of the ferroptosis process in atherosclerotic plaques is of great importance for diagnosing and treating AS. In this work, the rationally designed fluorescent probe FAS1 exhibited excellent advantages including large Stokes shift, sensitivity to environmental viscosity, good photostability, and improved water solubility. It also could co-locate with commercial lipid droplets (LDs) probes (BODIPY 493/503) well in RAW264.7 cells treated by the ferroptosis inducer. After self-assembly into nanoparticles and then encapsulation with macrophage membranes, the engineered FAS1@MM NPs could successfully target the atherosclerotic plaques in Western diet-induced apolipoprotein E knockout (ApoE-/-) mice and reveal the association of ferroptosis with AS through fluorescence imaging in vivo. This study may provide additional insights into the roles of ferroptosis in the diagnosis and treatment of AS.

Ferroptosis and metabolic syndrome and complications: association, mechanism, and translational applications

Metabolic syndrome is a medical condition characterized by several metabolic disorders in the body. Long-term metabolic disorders raise the risk of cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM). Therefore, it is essential to actively explore the aetiology of metabolic syndrome (MetS) and its comorbidities to provide effective treatment options. Ferroptosis is a new form of cell death that is characterized by iron overload, lipid peroxide accumulation, and decreased glutathione peroxidase 4(GPX4) activity, and it involves the pathological processes of a variety of diseases. Lipid deposition caused by lipid diseases and iron overload is significant in metabolic syndrome, providing the theoretical conditions for developing ferroptosis. Recent studies have found that the major molecules of ferroptosis are linked to common metabolic syndrome consequences, such as T2DM and atherosclerosis. In this review, we first discussed the mechanics of ferroptosis, the regulatory function of inducers and inhibitors of ferroptosis, and the significance of iron loading in MetS. Next, we summarized the role of ferroptosis in the pathogenesis of MetS, such as obesity, type 2 diabetes, and atherosclerosis. Finally, we discussed relevant ferroptosis-targeted therapies and raised some crucial issues of concern to provide directions for future Mets-related treatments and research.

An integrative analysis of single-cell and bulk transcriptome and bidirectional mendelian randomization analysis identified C1Q as a novel stimulated risk gene for Atherosclerosis

Background

The role of complement component 1q (C1Q) related genes on human atherosclerotic plaques (HAP) is less known. Our aim is to establish C1Q associated hub genes using single-cell RNA sequencing (scRNA-seq) and bulk RNA analysis to diagnose and predict HAP patients more effectively and investigate the association between C1Q and HAP (ischemic stroke) using bidirectional Mendelian randomization (MR) analysis.

Methods

HAP scRNA-seq and bulk-RNA data were download from the Gene Expression Omnibus (GEO) database. The C1Q-related hub genes was screened using the GBM, LASSO and XGBoost algorithms. We built machine learning models to diagnose and distinguish between types of atherosclerosis using generalized linear models and receiver operating characteristics (ROC) analyses. Further, we scored the HALLMARK_COMPLEMENT signaling pathway using ssGSEA and confirmed hub gene expression through qRT-PCR in RAW264.7 macrophages and apoE-/- mice. Furthermore, the risk association between C1Q and HAP was assessed through bidirectional MR analysis, with C1Q as exposure and ischemic stroke (IS, large artery atherosclerosis) as outcomes. Inverse variance weighting (IVW) was used as the main method.

Results

We utilized scRNA-seq dataset (GSE159677) to identify 24 cell clusters and 12 cell types, and revealed seven C1Q associated DEGs in both the scRNA-seq and GEO datasets. We then used GBM, LASSO and XGBoost to select C1QA and C1QC from the seven DEGs. Our findings indicated that both training and validation cohorts had satisfactory diagnostic accuracy for identifying patients with HPAs. Additionally, we confirmed SPI1 as a potential TF responsible for regulating the two hub genes in HAP. Our analysis further revealed that the HALLMARK_COMPLEMENT signaling pathway was correlated and activated with C1QA and C1QC. We confirmed high expression levels of C1QA, C1QC and SPI1 in ox-LDL-treated RAW264.7 macrophages and apoE-/- mice using qPCR. The results of MR indicated that there was a positive association between the genetic risk of C1Q and IS, as evidenced by an odds ratio (OR) of 1.118 (95%CI: 1.013-1.234, P = 0.027).

Conclusion

The authors have effectively developed and validated a novel diagnostic signature comprising two genes for HAP, while MR analysis has provided evidence supporting a favorable association of C1Q on IS.

Bioinformatics analyses of potentially common pathogenic networks for primary Sjögren's syndrome complicated with acute myocardial infarction

Both primary Sjögren's syndrome (pSS) and acute myocardial infarction (AMI) are intricately linked. However, their common mechanism is not fully understood. Herein, we examined the underlying network of molecular action associated with developing this complication. Datasets were downloaded from the GEO database. We performed enrichment and protein-protein interaction analyses and screened key genes. We used external datasets to confirm the diagnostic performance for these hub genes. Transcription factor and microRNA regulatory networks were constructed for the validated hub genes. Finally, drug prediction and molecular docking validation were performed. We identified 62 common DEGs, many of which were enriched regarding inflammation and immune response. 5 DEGs were found as key hub genes (IGSF6, MMP9, S100A8, MNDA, and NCF2). They had high diagnostic performance in external datasets. Functional enrichment of these five hub genes showed that they were associated with the adaptive immune response. The Type 1T helper cell showed the most association among all cell types related to AMI and pSS. We identified 36 common TFs and 49 identical TF-miRNAs. The drugs, including Benzo, dexamethasone, and NADP, were predicted as potential therapeutic agents. Herein, we revealed common networks involving pSS and AMI etiologies. Knowledge of these networks and hub genes can enhance research into their associated mechanism and the development of future robust therapy.

Crosstalk between ferroptosis and macrophages: potential value for targeted treatment in diseases

Ferroptosis is a newly identified form of programmed cell death that is connected to iron-dependent lipid peroxidization. It involves a variety of physiological processes involving iron metabolism, lipid metabolism, oxidative stress, and biosynthesis of nicotinamide adenine dinucleotide phosphate, glutathione, and coenzyme Q10. So far, it has been discovered to contribute to the pathological process of many diseases, such as myocardial infarction, acute kidney injury, atherosclerosis, and so on. Macrophages are innate immune system cells that regulate metabolism, phagocytize pathogens and dead cells, mediate inflammatory reactions, promote tissue repair, etc. Emerging evidence shows strong associations between macrophages and ferroptosis, which can provide us with a deeper comprehension of the pathological process of diseases and new targets for the treatments. In this review, we summarized the crosstalk between macrophages and ferroptosis and anatomized the application of this association in disease treatments, both non-neoplastic and neoplastic diseases. In addition, we have also addressed problems that remain to be investigated, in the hope of inspiring novel therapeutic strategies for diseases.

Ferroptosis: A potential target of macrophages in plaque vulnerability

Plaque vulnerability has been the subject of several recent studies aimed at reducing the risk of stroke and carotid artery stenosis. Atherosclerotic plaque development is a complex process involving inflammation mediated by macrophages. Plaques become more vulnerable when the equilibrium between macrophage recruitment and clearance is disturbed. Lipoperoxides, which are affected by iron levels in cells, are responsible for the cell death seen in ferroptosis. Ferroptosis results from lipoperoxide-induced mitochondrial membrane toxicity. Atherosclerosis in ApoE(-/-) mice is reduced when ferroptosis is inhibited and iron intake is limited. Single-cell sequencing revealed that a ferroptosis-related gene was substantially expressed in atherosclerosis-modeled macrophages. Since ferroptosis can be regulated, it offers hope as a non-invasive method of treating carotid plaque. In this study, we discuss the role of ferroptosis in atherosclerotic plaque vulnerability, including its mechanism, regulation, and potential future research directions.

lnc-MRGPRF-6:1 Promotes ox-LDL-Induced Macrophage Ferroptosis via Suppressing GPX4

Background

Ferroptosis, a newly discovered mode of cell death, emerges as a new target for atherosclerosis (AS). Long noncoding RNAs (lncRNAs) are involved in the regulation of ferroptosis. In our previous study, lnc-MRGPRF-6:1 was highly expressed in patients with coronary atherosclerotic disease (CAD) and closely associated with macrophage-mediated inflammation in AS. In the present study, we aim to investigate the role of lnc-MRGPRF-6:1 in oxidized-low-density lipoprotein (ox-LDL)-induced macrophage ferroptosis in AS.

Methods

Firstly, ox-LDL-treated macrophages were used to simulate macrophage injury in AS. Then, ferroptosis-related biomarkers and mitochondrial morphology were detected and observed in ox-LDL-treated macrophages. Subsequently, we constructed lnc-MRGPRF-6:1 knockdown and overexpression of THP-1-derived macrophages and investigated the role of lnc-MRGPRF-6:1 in ox-LDL-induced ferroptosis. Then human monocytes were isolated successfully and were used to explore the role of lnc-MRGPRF-6:1 in macrophage ferroptosis. Likely, we constructed lnc-MRGPRF-6:1 knockdown and overexpression of human monocyte-derived macrophages and detected the expression levels of ferroptosis-related biomarkers. Then, transcriptome sequencing, literature searching, and following quantitative real-time polymerase chain reaction and western blot were implemented to explore specific signaling pathway in the process. It was demonstrated that lnc-MRGPRF-6:1 may regulate ox-LDL-induced macrophage ferroptosis through glutathione peroxidase 4 (GPX4). Eventually, the correlation between lnc-MRGPRF-6:1 and GPX4 was measured in monocyte-derived macrophages of CAD patients and controls.

Results

The ox-LDL-induced injury in macrophages was involved in ferroptosis. The knockdown of lnc-MRGPRF-6:1 could alleviate ox-LDL-induced ferroptosis in macrophages. Meanwhile, the overexpression of lnc-MRGPRF-6:1 could intensify ox-LDL-induced ferroptosis. Furthermore, the knockdown of lnc-MRGPRF-6:1 could alleviate the decrease of GPX4 induced by RAS-selective lethal compounds 3 (RSL-3). These indicated that lnc-MRGPRF-6:1 may suppress GPX4 to induce macrophage ferroptosis. Eventually, lnc-MRGPRF-6:1 was highly expressed in the monocyte-derived macrophages of CAD patients and was negatively correlated with the expression of GPX4.

Conclusion

lnc-MRGPRF-6:1 can promote ox-LDL-induced macrophage ferroptosis through inhibiting GPX4.

Integrating RNA-seq and scRNA-seq to explore the mechanism of macrophage ferroptosis associated with COPD

Aims: Our study focused on whether macrophages ferroptosis is associated with the pathogenesis of chronic obstructive pulmonary disease (COPD) or not.

Main methods: We first identified macrophage module genes by weighted gene co-expression network analysis (WGCNA) in RNA sequencing (RNA-seq) date from COPD, and then identified macrophage marker genes by comprehensive analysis of single-cell RNA sequencing (scRNA-seq) data from COPD macrophages. There were 126 macrophage marker genes identified, and functional enrichment analyses indicated that ferroptosis pathway genes were significantly enriched. Secondly, we identified eight macrophage ferroptosis related genes and based on these eight genes, we performed co-expression analysis and drug prediction. Thirdly, two biomarkers (SOCS1 and HSPB1) were screened by the least absolute shrinkage and selection operator (LASSO), random forest (RF), and support vector machine-recursive feature elimination (SVM-RFE) and established an artificial neural network (ANN) for diagnosis. Subsequently, the biomarkers were validated in the dataset and validation set. These two biomarkers were then subjected to single gene-gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA) analysis, and the ceRNA network was constructed. Finally, we carried out molecular validation with COPD models in vitro for cell counting kit-8 (CCK8) experiments, Western blot and quantitative real-time PCR (qRT-PCR) analysis and transmission electron microscopy (TEM).

Key findings: This study revealed the vital role of macrophage ferroptosis in COPD, and novel biomarkers (SOCS1 and HSPB1) may be involved in the pathogenesis of COPD by regulating macrophage ferroptosis.

Significance: Taken together, our results suggest that targeting SOCS1 and HSPB1 could treat COPD by inhibiting macrophage ferroptosis.

Heterogeneity of macrophages in atherosclerosis revealed by single-cell RNA sequencing

Technology at the single-cell level has advanced dramatically in characterizing molecular heterogeneity. These technologies have enabled cell subtype diversity to be seen in all tissues, including atherosclerotic plaques. Critical in atherosclerosis pathogenesis and progression are macrophages. Previous studies have only determined macrophage phenotypes within the plaque, mainly by bulk analysis. However, recent progress in single-cell technologies now enables the comprehensive mapping of macrophage subsets and phenotypes present in plaques. In this review, we have updated and discussed the definition and classification of macrophage subsets in mice and humans using single-cell RNA sequencing. We summarized the different classification methods and perspectives: traditional classification with an updated scoring system, inflammatory macrophages, foamy macrophages, and atherosclerotic-resident macrophages. In addition, some special types of macrophages were identified by specific markers, including IFN-inducible and cavity macrophages. Furthermore, we discussed macrophage subset-specific markers and their functions. In the future, these novel insights into the characteristics and phenotypes of these macrophage subsets within atherosclerotic plaques can provide additional therapeutic targets for cardiovascular diseases.

Deciphering the sequential changes of monocytes/macrophages in the progression of IDD with longitudinal approach using single-cell transcriptome

Intervertebral disk degeneration (IDD) is a chronic inflammatory disease with intricate connections between immune infiltration and oxidative stress (OS). Complex cell niches exist in degenerative intervertebral disk (IVD) and interact with each other and regulate the disk homeostasis together. However, few studies have used longitudinal approach to describe the immune response of IDD progression. Here, we conducted conjoint analysis of bulk-RNA sequencing and single-cell sequencing, together with a series of techniques like weighted gene co-expression network analysis (WGCNA), immune infiltration analysis, and differential analysis, to systematically decipher the difference in OS-related functions of different cell populations within degenerative IVD tissues, and further depicted the longitudinal alterations of immune cells, especially monocytes/macrophages in the progression of IDD. The OS-related genes CYP1A1, MMP1, CCND1, and NQO1 are highly expressed and might be diagnostic biomarkers for the progression of IDD. Further landscape of IVD microenvironment showed distinct changes in cell proportions and characteristics at late degeneration compared to early degeneration of IDD. Monocytes/macrophages were classified into five distinct subpopulations with different roles. The trajectory lineage analysis revealed transcriptome alterations from effector monocytes/macrophages and regulatory macrophages to other subtypes during the evolution process and identified monocytes/macrophage subpopulations that had rapidly experienced the activation of inflammatory or anti-inflammatory responses. This study further proposed that personalized therapeutic strategies are needed to be formulated based on specific monocyte/macrophage subtypes and degenerative stages of IDD.

Relationships of ferroptosis-related genes with the pathogenesis in polycystic ovary syndrome

Background

Numerous studies have suggested that ferroptosis plays a significant role in the development of polycystic ovary syndrome (PCOS), but the mechanism remains unclear.

Methods

In this study, we explored the role of ferroptosis-related genes in the pathogenesis of PCOS using a comprehensive bioinformatics method. First, we downloaded several Gene Expression Omnibus (GEO) datasets and combined them into a meta-GEO dataset. Differential expression analysis was performed to screen for significant ferroptosis-related genes between the normal and PCOS samples. The least absolute shrinkage selection operator regression and support vector machine-recursive feature elimination were used to select the best signs to construct a PCOS diagnostic model. Receiver operating characteristic curve analysis and decision curve analysis were applied to test the performance of the model. Finally, a ceRNA network-related ferroptosis gene was constructed.

Results

Five genes, namely, NOX1, ACVR1B, PHF21A, FTL, and GALNT14, were identified from 10 differentially expressed ferroptosis-related genes to construct a PCOS diagnostic model. Finally, a ceRNA network including 117 lncRNAs, 67 miRNAs, and five ferroptosis-related genes was constructed.

Conclusion

Our study identified five ferroptosis-related genes that may be involved in the pathogenesis of PCOS, which may provide a novel perspective for the clinical diagnosis and treatment of PCOS.

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.

Ferroptosis: A potential target for the intervention of intervertebral disc degeneration

Ferroptosis, an iron-dependent form of programmed cell death marked by phospholipid peroxidation, is regulated by complex cellular metabolic pathways including lipid metabolism, iron balance, redox homeostasis, and mitochondrial activity. Initial research regarding the mechanism of ferroptosis mainly focused on the solute carrier family 7 member 11/glutathione/glutathione peroxidase 4 (GPX4) signal pathway. Recently, novel mechanisms of ferroptosis, independent of GPX4, have been discovered. Numerous pathologies associated with extensive lipid peroxidation, such as drug-resistant cancers, ischemic organ injuries, and neurodegenerative diseases, are driven by ferroptosis. Ferroptosis is a new therapeutic target for the intervention of IVDD. The role of ferroptosis in the modulation of intervertebral disc degeneration (IVDD) is a significant topic of interest. This is a novel research topic, and research on the mechanisms of IVDD and ferroptosis is ongoing. Herein, we aim to review and discuss the literature to explore the mechanisms of ferroptosis, the relationship between IVDD and ferroptosis, and the regulatory networks in the cells of the nucleus pulposus, annulus fibrosus, and cartilage endplate to provide references for future basic research and clinical translation for IVDD treatment.