Cardiac Fibroblasts Promote Ferroptosis in Atrial Fibrillation by Secreting Exo-miR-23a-3p Targeting SLC7A11

The intersection of ferroptosis and non-coding RNAs: a novel approach to ovarian cancer

Understanding the core principles of ovarian cancer has been significantly improved through the exploration of Ferroptosis, a type of cell death triggered by iron that leads to an increase in lipid peroxides. Current research has shed light on the critical functions of non-coding RNAs, such as circRNAs, lncRNAs, and miRNAs, in regulating ferroptosis in ovarian cancer. The aim of this paper is to comprehensively analyze how ncRNAs influence the development of ferroptosis in ovarian cancer cells. In-depth exploration is undertaken to understand the intricate ways in which ncRNAs regulate essential elements of ferroptosis, including iron management and lipid peroxidation levels. We also investigate their significant involvement in the progression of this type of cellular demise. It should be emphasized that ncRNAs can impact the synthesis of crucial proteins, such as GPX4, a key contributor to the cellular defense against oxidation, and ACSL4, involved in lipid formation. In addition, we examine the correlation between ncRNAs and well-known pathways associated with oxidative stress and cell death. The consequences of these discoveries are noteworthy, since focusing on particular ncRNAs could potentially render ovarian cancer cells more vulnerable to ferroptosis, effectively combating drug resistance problems. This discussion highlights the growing significance of ncRNAs in governing ferroptosis and their potential as useful biomarkers and treatment targets for ovarian cancer. We intend to promote additional research into the involvement of ncRNAs in controlling ferroptosis, based on current findings, with the ultimate goal of informing targeted therapeutic strategies and improving long-term treatment outcomes for individuals suffering from OC.

Roles and Therapeutic Targeting of Exosomes in Sepsis-Induced Cardiomyopathy

Sepsis-induced cardiomyopathy (SICM) is a complex and fatal manifestation of sepsis, characterised by myocardial dysfunction that exacerbates the clinical prognosis in septic patients. While the pathophysiology of SICM remains incompletely understood, emerging evidence highlights the multifaceted functions of exosomes, small membrane-bound extracellular vesicles, in mediating the inflammatory responses and cardiac dysfunction involved in this condition. During sepsis, exosomes are secreted by various cells, such as cardiomyocytes, endothelial cells and macrophages, which serve as critical messengers, transferring proteins, lipids and RNA molecules that influence recipient cells, thus affecting cellular functions and disease progression. This review summarises the pathophysiology of SICM and the basics of exosomes and focuses on exosome-mediated mechanisms in SICM, including their role in inflammation, oxidative stress, mitochondrial dysfunction and myocardial injury, offering novel insights into the exosome-based therapeutic strategies in SICM.

LncRNA Growth Arrest Specific 5 Promotes Glucose Metabolism Reprogramming Via the IGF2BP1/SIX1 Axis and Inhibits Ferroptosis of Endothelial Progenitor Cells Via the miR-23a-3p/SLC7A11 Axis in Coronary Heart Disease

BACKGROUND

Growth arrest specific 5 (GAS5) is a long noncoding RNA (lncRNA) that regulates the function of cardiovascular cells in various cardiovascular diseases. The current study delved into the regulation of GAS5 on the function of endothelial progenitor cells (EPCs) and its potential regulatory mechanism in coronary heart disease (CHD).

METHODS

Reverse transcription-quantitative polymerase chain reaction was used to detect GAS5 expression in the blood samples and EPCs from CHD patients and healthy controls. Cell Counting Kit-8, colony formation, flow cytometry, and transwell assays were performed to evaluate cell phenotype of EPCs. Ferroptosis was detected by the measurement of Fe2+, malondialdehyde, GSH, and reactive oxygen species (ROS) levels. Glycolysis was determined by extracellular acidification rate (ECAR), oxygen consumption rate (OCR), glucose uptake and lactate production.

RESULTS

Growth arrest specific 5 was downregulated in the blood samples and EPCs from CHD patients. Growth arrest specific 5 deficiency suppressed EPC proliferative capacity, migration, invasion and facilitated EPC apoptosis while GAS5 overexpression showed contrary effects. Moreover, GAS5 silencing inhibited the glucose metabolic reprogramming, as evidenced by the reduced ECAR, glycolysis capacity, ATP, glucose uptake and lactate production, and elevated OCR. Additionally, GAS5 overexpression attenuated the erastin-induced ferroptosis of EPCs. Growth arrest specific 5 could bind to IGF2BP1 to enhance the mRNA stability of glycolysis transcriptional regulator SIX1. Growth arrest specific 5 interacted with miR-23a-3p to regulate SLC7A11 expression. GAS5 promoted glucose metabolic reprogramming of EPCs by upregulating SIX1 and inhibited EPC ferroptosis by elevating SLC7A11.

CONCLUSION

Growth arrest specific 5 promotes glucose metabolic reprogramming and represses ferroptosis of EPCs via the IGF2BP1/SIX1 and miR-23a-3p/SLC7A11 dual-regulatory pathways in CHD.

Myocardial ferroptosis may exacerbate the progression of atrial fibrillation through isolevuglandins

Atrial fibrillation (AF) poses a serious health threat to human health and causes various adverse effects. It is currently the most common type of arrhythmia in adults. Long-term AF induces a series of heart-remodeling events, including mainly cardiac structural remodeling and electrical remodeling, which further exacerbates AF. The oxidative stress has been shown to play a role in inducing myocardial remodeling and the progression of AF. Recent studies have shown that ferroptosis occurs in the myocardium of patients with AF, which exacerbates oxidative stress and may constitute a new mechanism for the progression of AF. However, it is unknown to us how ferroptosis is involved in the initiation and maintenance of AF, so the purpose of this review is to elucidate the possible underlying mechanism of ferroptosis exacerbating AF. We reviewed the latest studies on myocardial ferroptosis and AF and speculate that the lipid peroxidation products isolevuglandins (IsoLGs), which are produced during myocardial ferroptosis, may be involved in the progression of AF through two pathways: (1) IsoLGs inhibit the degradation of myocardial collagen, worsening myocardial fibrosis; and (2) IsoLGs promote the occurrence of amyloidosis in the myocardium and increase the risk of AF. Consequently, we aim to prevent the progression of atrial fibrillation by either suppressing the production of IsoLGs or enhancing their clearance process to inhibit ferroptosis in the myocardium, improving the prognosis of patients with AF.

Role of ferroptosis in atrial fibrillation: a review

Cardiovascular disease remains the leading cause of mortality, with atrial fibrillation emerging as one of the most common conditions encountered in clinical practice. However, its underlying mechanisms remain poorly understood, prompting ongoing research. Ferroptosis, a recently discovered form of regulated cell death characterized by lipid peroxidation and disrupted cellular redox balance leading to cell death due to iron overload, has attracted significant attention. Since its identification, ferroptosis has been extensively studied in various contexts, including cancer, stroke, myocardial ischemia/reperfusion injury, and heart failure. Growing evidence suggests that ferroptosis may also play a critical role in the onset and progression of atrial fibrillation, though research in this area is still limited. This article provides a concise overview of the potential mechanisms by which ferroptosis may contribute to the pathogenesis of atrial fibrillation.

Exploring ferroptosis and miRNAs: implications for cancer modulation and therapy

Ferroptosis is a novel, iron-dependent form of non-apoptotic cell death characterized by the accumulation of lipid reactive oxygen species (ROS) and mitochondrial shrinkage. It is closely associated with the onset and progression of various diseases, especially cancer, at all stages, making it a key focus of research for developing therapeutic strategies. Numerous studies have explored the role of microRNAs (miRNAs) in regulating ferroptosis by modulating the expression of critical genes involved in iron metabolism and lipid peroxidation. Due to their diversity, unique properties, and dynamic expression patterns in diseases, exosomal miRNAs are emerging as promising biomarkers. Exosomes act as biological messengers, delivering miRNAs to target cells through specific internalization, thus influencing the ferroptosis response in recipient cells. This review summarizes the roles of miRNAs, with particular focus on exosomal miRNAs, in ferroptosis and their implications for cancer pathology. By examining the molecular mechanisms of miRNAs, we aim to provide valuable insights into potential therapeutic approaches.

Epigenetic regulation and post-translational modifications of ferroptosis-related factors in cardiovascular diseases

As an important element of the human body, iron participates in numerous physiological and biochemical reactions. In the past decade, ferroptosis (a form of iron-dependent regulated cell death) has been reported to contribute to the pathogenesis and progression of various diseases. The stability of iron in cardiomyocytes is crucial for the maintenance of normal physiological cardiac activity. Ferroptosis has been detected in many cardiovascular diseases (CVDs), including coronary heart disease, myocardial ischemia-reperfusion injury, heart failure, and chemotherapy-induced myocardial damage. In cardiomyocytes, epigenetic regulation and post-translational modifications regulate the expression of ferroptosis-related factors, maintain iron homeostasis, and participate in the progression of CVDs. Currently, there is no detailed mechanism to explain the relationship between epigenetic regulation and ferroptosis in CVDs. In this review, we provide an initial summary of the core mechanisms of ferroptosis in cardiomyocytes, with first focus on the epigenetic regulation and expression of ferroptosis-related factors in the context of common cardiovascular diseases. We anticipate that the new insights into the pathogenesis of CVDs provided here will inspire the development of clinical interventions to specifically target the active sites of these factors, reducing the harmfulness of ferroptosis to human health.

An emerging double‑edged sword role of ferroptosis in cardiovascular disease (Review)

The pathophysiology of cardiovascular disease (CVD) is complex and presents a serious threat to human health. Cardiomyocyte loss serves a pivotal role in both the onset and progression of CVD. Among various forms of programmed cell death, ferroptosis, along with apoptosis, autophagy and pyroptosis, is closely linked to the advancement of CVD. Ferroptosis, a mechanism of cell death, is driven by the buildup of oxidized lipids and excess iron. This pathway is modulated by lipid, amino acid and iron metabolism. Key characteristics of ferroptosis include disrupted iron homeostasis, increased peroxidation of polyunsaturated fatty acids due to reactive oxygen species, decreased glutathione levels and inactivation of glutathione peroxidase 4. Treatments targeting ferroptosis could potentially prevent or alleviate CVD by inhibiting the ferroptosis pathway. Ferroptosis is integral to the pathogenesis of several types of CVD and inhibiting its occurrence in cardiomyocytes could be a promising therapeutic strategy for the future treatment of CVD. The present review provided an in‑depth analysis of advancements in understanding the mechanisms underlying ferroptosis. The present manuscript summarized the interplay between ferroptosis and CVDs, highlighting its dual roles in these conditions. Additionally, potential therapeutic targets within the ferroptosis pathway were discussed, alongside the current limitations and future directions of these novel treatment strategies. The present review may offer novel insights into preventive and therapeutic approaches for CVDs.

The crosstalk between exosomal miRNA and ferroptosis: A narrative review

Ferroptosis is a type of cell death that multiple mechanisms and pathways contribute to the positive and negative regulation of it. For example, increased levels of reactive oxygen species (ROS) induce ferroptosis. ferroptosis unlike apoptosis, it is not dependent on caspases, but is dependent on iron. Exosomes are membrane-bound vesicles with a size of about 30 to 150 nm, contain various cellular components, including DNA, RNA, microRNAs (miRNAs), lipids, and proteins, which are genetically similar to their cells of origin. Exosomes are found in all bodily fluids, including blood, saliva, and urine. Cells often release exosomes after their fusion with the cell membrane. They play an important role in immune regulation and cell-cell communication. miRNAs, which are noncoding RNAs with a length of about 18 to 24 nucleotides, are involved in regulating gene expression after transcription. Emerging data suggests that exosomal miRNAs are implicated in various pathophysiological mechanisms of cells, including metastasis, drug resistance, and cell death. In addition, functional studies have indicated that exosomal miRNAs can play a key role in the modulation of cell death by regulating ferroptosis. Therefore, in this review, given the importance of exosomal miRNAs in ferroptosis, we decided to elucidate the relationship between exosomal miRNAs and ferroptosis in various diseases.

Exosomes activate hippocampal microglia in atrial fibrillation through long-distance heart-brain communication

BACKGROUND

There is growing evidence that atrial fibrillation (AF) is a risk factor for cognitive impairment (CI) and dementia in the presence or absence of stroke. The purpose of this study was to explore the mechanism of CI caused by AF.

METHODS

Eighteen male canines were randomly divided into a sham group, a pacing group, and a pacing + GW4869 group. An experimental model of AF was established by rapid atrial pacing (450 beats/min) for 2 weeks, and the sham group received pacemaker implantation without atrial pacing. The GW4869 group received an intravenous GW4869 injection (0.3 mg/kg, once a day) during pacing. All canines were locally injected with Ad-CD63-RFP in epicardial adipose tissue (EAT) to trace the exosomes. Ultracentrifugation was employed to isolate EAT-derived exosomes, followed by RNA sequencing and quantitative real-time PCR (qRT-PCR) to assess RNA in both exosomes and hippocampal tissue. The miRanda database was used to predict the targeting relationships between miRNA and mRNA, which were further validated by luciferase reporter assays. Western blot analysis was conducted to detect exosomal markers (CD63, CD81, TSG101) in EAT exosomes, while immunofluorescence was used to detect Ad-CD63-RFP signals in both EAT and hippocampal tissues, as well as microglial activation marker IBA-1. To further explore the effects of exosomes on microglial cells, in vitro experiments using brain microvascular endothelial cells (bEnd3) and microglial cells (BV2) were conducted. IBA-1 expression and RNA levels in BV2 cells were analyzed by immunofluorescence and qRT-PCR, respectively.

RESULTS

After 14 days of pacing of the canine atrium, compared to the sham group, both the pacing and GW4869 groups exhibited an increased number of AF inductions, along with prolonged AF duration. The fluorescence intensity of Ad-CD63-RFP and the microglial activation marker IBA-1 were markedly greater in the hippocampus. RNA sequencing showed that the differentially expressed gene cfa-miR-22e in EAT exosomes was upregulated, and its target gene IL33 was downregulated in the hippocampus. qRT-PCR showed that the levels of cfa-miR-22e were increased in both EAT exosomes and the hippocampus, while the expression of IL-33, a target of cfa-miR-22e, was decreased in the hippocampus. The administration of GW4869 abolished these effects. The in vitro results from bEnd3 and BV2 cell experiments were consistent with the conclusions drawn from the in vivo studies.

CONCLUSION

Our study indicated that the exosomes secreted by EAT in canines with AF can penetrate the BBB and activate microglia in the hippocampus through the cfa-miR-22e/IL33 signalling pathway.

Assessing the use of blood microRNA expression patterns for predictive diagnosis of myxomatous mitral valve disease in dogs

Background

Myxomatous mitral valve disease (MMVD) is a common, acquired, and progressive canine heart disease. The presence of heart murmur and current cardiac biomarkers are useful in MMVD cases but are not sufficiently discriminatory for staging an individual patient.

Objectives

This study aimed to conduct a preliminary assessment of canine serum and plasma expression profiles of 15 selected miRNA markers for accurate discrimination between MMVD patients and healthy controls. Additionally, we aim to evaluate the effectiveness of this method in differentiating between pre-clinical (stage B1/B2) and clinical (stage C/D) MMVD patients.

Animals

Client-owned dogs (n = 123) were recruited for the study. Following sample exclusions (n = 26), healthy controls (n = 50) and MMVD cases (n = 47) were analyzed.

Methods

A multicenter, cross-sectional, prospective investigation was conducted. MicroRNA expression profiles were compared among dogs, and these profiles were used as input for predictive modeling. This approach aimed to distinguish between healthy controls and MMVD patients, as well as to achieve a more fine-grained differentiation between pre-clinical and clinical MMVD patients.

Results

Performance metrics revealed a compelling ability of the method to differentiate healthy controls from dogs with MMVD (sensitivity 0.85; specificity 0.82; and accuracy 0.83). For the discrimination between the pre-clinical (n = 29) and clinical (n = 18) MMVD cases, the results were promising (sensitivity 0.61; specificity 0.79; and accuracy 0.73).

Conclusion and clinical importance

The use of miRNA expression profiles in combination with customized probabilistic predictive modeling shows good scope to devise a reliable diagnostic tool to distinguish healthy controls from MMVD cases (stages B1 to D). Investigation into the ability to discriminate between the pre-clinical and clinical MMVD cases using the same method yielded promising early results, which could be further enhanced with data from an increased study population.

Noncoding RNAs regulating ferroptosis in cardiovascular diseases: novel roles and therapeutic strategies

The morbidity and mortality rates of cardiovascular diseases (CVDs) are increasing; thus, they impose substantial health and economic burdens worldwide, and effective interventions are needed for immediate resolution of this issue. Recent studies have suggested that noncoding RNAs (ncRNAs) play critical roles in the occurrence and development of CVDs and are potential therapeutic targets and novel biomarkers for these diseases. Newly discovered modes of cell death, including necroptosis, pyroptosis, apoptosis, autophagy-dependent cell death and ferroptosis, also play key roles in CVD progression. However, ferroptosis, which differs from the other aforementioned forms of regulated cell death in terms of cell morphology, biochemistry and inhereditability, is a unique iron-dependent mode of nonapoptotic cell death induced by abnormal iron metabolism and excessive accumulation of iron-dependent lipid peroxides and reactive oxygen species (ROS). Increasing evidence has confirmed that ncRNA-mediated ferroptosis is involved in regulating tissue homeostasis and CVD-related pathophysiological conditions, such as cardiac ischemia/reperfusion (I/R) injury, myocardial infarction (MI), atrial fibrillation (AF), cardiomyopathy and heart failure (HF). In this review, we summarize the underlying mechanism of ferroptosis, discuss the pathophysiological effects of ncRNA-mediated ferroptosis in CVDs and provide ideas for effective therapeutic strategies.

Exosome is a Fancy Mobile Sower of Ferroptosis

Exosomes, nano-sized small extracellular vesicles, have been shown to serve as mediators between intercellular communications by transferring bioactive molecules, such as non-coding RNA, proteins, and lipids from secretory to recipient cells, modulating a variety of physiological and pathophysiological processes. Recent studies have gradually demonstrated that altered exosome charges may represent a key mechanism driving the pathological process of ferroptosis. This review summarizes the potential mechanisms and signal pathways relevant to ferroptosis and then discusses the roles of exosome in ferroptosis. As well as transporting iron, exosomes may also indirectly convey factors related to ferroptosis. Furthermore, ferroptosis may be transmitted to adjacent cells through exosomes, resulting in cascading effects. It is expected that further research on exosomes will be conducted to explore their potential in ferroptosis and will lead to the creation of new therapeutic avenues for clinical diseases.

Bioinformatics analysis of neutrophil-associated hub genes and ceRNA network construction in septic cardiomyopathy

Septic cardiomyopathy (SCM) is a critical sepsis complication characterized by reversible cardiac depression during early septic shock. Neutrophils, integral to innate immunity, can mediate organ damage when abnormal, but their specific role in sepsis-induced myocardial damage remains elusive. Our study focuses on elucidating the role of Neutrophil-Related Genes (NRGs) in SCM, finding early diagnosis and treatment biomarkers. We identified shared differentially expressed genes (DEGs) from datasets GSE79962 and GSE44363 and pinpointed hub DEGs using the cytoHubba plugin in Cytoscape software. The Neutrophil-Related Hub Gene (NRHG) MRC1 was identified via intersecting hub DEGs with NRGs from WGCNA. We validated MRC1's abnormal expression in SCM using our data and external datasets. Furthermore, a neutrophil-related ceRNA network (AC145207.5/ miR-23a-3p/MRC1) was constructed and validated. Our findings reveal MRC1 as a potential NRHG in SCM pathogenesis, offering insights into neutrophil-mediated mechanisms in SCM and providing a novel molecular target for early diagnosis and intervention in SCM.

Identification of common mechanisms and biomarkers of atrial fibrillation and heart failure based on machine learning

AIMS

Atrial fibrillation (AF) is the most common arrhythmia. Heart failure (HF) is a disease caused by heart dysfunction. The prevalence of AF and HF were progressively increasing over time. The co-existence of AF and HF presents a significant therapeutic challenge. In order to provide new ideas for the diagnosis of AF and HF, it is necessary to carry out biomarker related studies.

METHODS AND RESULTS

The training set and validation set data of AF and HF patient samples were downloaded from the GEO database, 'limma' was used to compare the differences in gene expression levels between the disease group and the normal group to screen for differentially expressed genes (DEGs). Weighted correlation network analysis (WGCNA) identified the modules with the highest positive correlation with AF and HF. Functional enrichment and PPI network construction of key genes were carried out. Biomarkers were screened by machine learning. The infiltration of immune cells in AF and HF groups was evaluated by R-packet 'CIBERSORT'. The miRNA network was constructed and potential therapeutic agents for biomarker genes were predicted through the drugbank database. Through WGCNA analysis, it was found that the modules most positively correlated with AF and HF were MEturquoise (r = 0.21, P value = 0.09) and MEbrown (r = 0.62, P value = 8e-12), respectively. We screened 25 genes that were highly correlated with both AF and HF. Lasso regression analysis results showed 7 and 20 core genes in AF and HF groups, respectively. The top 20 important genes in AF and HF groups were obtained as core genes by RF model analysis. Four biomarkers were obtained after the intersection of core genes in four groups, namely, GLUL, NCF2, S100A12, and SRGN. The diagnostic efficacy of four genes in AF validation sets was good (AUC: GLUL 0.76, NCF2 0.64, S100A12 0.68, and SRGN 0.76), as well as in the HF validation set (AUC: GLUL 0.76, NCF2 0.84, S100A12 0.92, and SRGN 0.68). The highest correlation with neutrophils was observed for GLUL, NCF2, and S100A12, while SRGN exhibited the strongest correlation with T cells CD4 memory resting in the AF group. GLUL, NCF2, S100A12, and SRGN were most associated with neutrophils in the HF group. A total of 101 miRNAs were predicted by four genes, and GLUL, NCF2, and S100A12 predicted a total of 10 potential therapeutic agents.

CONCLUSIONS

We identified four biological markers that are highly correlated with AF and HF, namely, GLUL, NCF2, S100A12, and SRGN. Our findings provide theoretical basis for the clinical diagnosis and treatment of AF and HF.

Atrial fibroblast-derived exosomal miR-21 upregulate myocardial KCa3.1 via the PI3K-Akt pathway during rapid pacing

Background

Fibroblast-derived exosomes can regulate the electrical remodeling of cardiomyocytes, and the intermediate-conductance calcium-activated potassium channel (KCa3.1) is important in atrial electrical remodeling. However, the underlying molecular mechanisms remain unclear. This study aimed to investigate the regulation of cardiac electrophysiology by exosomes linked to KCa3.1.

Methods

Atrial myocytes (AMs) and atrial fibroblasts were isolated from Sprague-Dawley suckling rats and cultured individually. The cellular atrial fibrillation (AF) model was established via electrical stimulation (1.0 v/cm, 10 Hz), and fibroblast-derived exosomes were isolated via ultracentrifugation. Exosomes were co-cultured with AMs to investigate their influences on KCa3.1 and the underlying mechanisms. Nanoparticle tracking analysis and transmission electron microscopy were used to measure exosome particle sizes and concentrations. Whole-cell patch clamp was applied to record the current density of KCa3.1 and action potential duration (APD). The expression of miR-21-5p was detected by reverse-transcription polymerase chain reaction (RT-PCR). Western blotting or immunofluorescence was used to measure the expression of exosomal markers, Akt phosphorylation, and KCa3.1.

Results

Rapid pacing promoted the secretion of exosomes from atrial fibroblasts and miR-21-5p expression in atrial fibroblasts and exosomes. KCa3.1 protein expression and current density significantly increased, and APD50 and APD90 were sharply shortened after rapid pacing in AMs. TRAM-34 (KCa3.1 blocker) extended APD and reduced susceptibility to AF. KCa3.1 and P-AKT expressions were amplified after co-culturing AMs with exosomes secreted by atrial fibroblasts. In contrast, the increase in KCa3.1 expression was reversed after the cells were co-cultured with exosomes secreted by atrial fibroblasts that were transfected with miR-21-5p inhibitors or after the use of LY294002, a PI3K/Akt pathway inhibitor.

Conclusions

Rapid pacing promoted the secretion of exosomes from fibroblasts, and miR-21-5p was upregulated in exosomes. Moreover, the miR-21-5p-enriched exosomes upregulated KCa3.1 expression in AMs via the PI3K/Akt pathway.

The role of iron overload and ferroptosis in arrhythmia pathogenesis

Ferroptosis is a newly discovered form of programmed cell death triggered by intracellular iron overload, which leads to the accumulation of lipid peroxides in various cells. It has been implicated in the pathogenesis and progression of various diseases, including tumors, neurological disorders, and cardiovascular diseases. The intricate mechanism underlying ferroptosis involves an imbalance between the oxidation and antioxidant systems, disturbances in iron metabolism, membrane lipid peroxidation, and dysregulation of amino acid metabolism. We highlight the key molecular mechanisms governing iron overload and ferroptosis, and discuss potential molecular pathways linking ferroptosis with arrhythmias.

The crosstalk between exosomes and ferroptosis: a review

Exosomes are a subtype of extracellular vesicles composed of bioactive molecules, including nucleic acids, proteins, and lipids. Exosomes are generated by the fusion of intracellular multivesicular bodies (MVBs) with the cell membrane and subsequently released into the extracellular space to participate in intercellular communication and diverse biological processes within target cells. As a crucial mediator, exosomes have been implicated in regulating ferroptosis-an iron-dependent programmed cell death characterized by lipid peroxide accumulation induced by reactive oxygen species. The involvement of exosomes in iron, lipid, and amino acid metabolism contributes to their regulatory role in specific mechanisms underlying how exosomes modulate ferroptosis, which remains incompletely understood, and some related studies are still preliminary. Therefore, targeting the regulation of ferroptosis by exosomes holds promise for future clinical treatment strategies across various diseases. This review aims to provide insights into the pathophysiology and mechanisms governing the interaction between exosomes and ferroptosis and their implications in disease development and treatment to serve as a reference for further research.

The Role of Ferroptosis in Atrial Fibrillation: A Promising Future

Atrial fibrillation (AF) is one of the most common cardiac arrhythmias, with its diagnosis being closely tied to higher rates of cardiovascular morbidity and mortality. AF is associated with a range of dangerous complications including stroke and heart failure, making it a key driver of healthcare spending and a major threat to global public health. The precise mechanisms that govern AF incidence and the onset of related complications, however, remain uncertain. Ferroptotic cell death has been the focus of rising interest in the cardiac arrhythmias, and there is recent evidence supporting a role for atrial ferroptosis as a mediator of AF development. Interventional strategies focused on ferroptotic activity, such as novel ferroptosis inhibitors, have also shown promise as a means of protecting against AF through their ability to reduce iron overload. In this review, we provide a summary of the proposed mechanisms whereby ferroptosis contributes to the pathophysiology of AF and their therapeutic implications.

M2 macrophage‑derived exosomes alleviate KCa3.1 channel expression in rapidly paced HL‑1 myocytes via the NF‑κB (p65)/STAT3 signaling pathway

The present study was designed to explore the role of M2 macrophage‑derived exosomes (M2‑exos) on the KCa3.1 channel in a cellular atrial fibrillation (AF) model using rapidly paced HL‑1 myocytes. M2 macrophages and M2‑exos were isolated and identified. MicroRNA (miR)‑146a‑5p levels in M2 macrophages and M2‑exos were quantified using reverse transcription‑quantitative PCR (RT‑qPCR). HL‑1 myocytes were randomly divided into six groups: Control group, pacing group, pacing + coculture group (pacing HL‑1 cells cocultured with M2‑exos), pacing + mimic‑miR‑146a‑5p group, pacing + NC‑miR‑146a‑5p group and pacing + pyrrolidine dithiocarbamate (PDTC; a special blocker of the NF‑κB signaling pathway) group. Transmission electron microscopy, nanoparticle tracking analysis, western blotting, RT‑qPCR and immunohistochemistry were performed in the present study. A whole‑cell clamp was also applied to record the current density of KCa3.1 and action potential duration (APD) in each group. The results revealed that miR‑146a‑5p was highly expressed in both M2 macrophages and M2‑exos. Pacing HL‑1 cells led to a shorter APD, an increased KCa3.1 current density and higher protein levels of KCa3.1, phosphorylated (p‑)NF‑κB p65, p‑STAT3 and IL‑1β compared with the control group. M2‑exos, miR‑146a‑5p‑mimic and PDTC both reduced the protein expression of KCa3.1, p‑NF‑κB p65, p‑STAT3 and IL‑1β and the current density of KCa3.1, resulting in a longer APD in the pacing HL‑1 cells. In conclusion, M2‑exos and their cargo, which comprised miR‑146a‑5p, decreased KCa3.1 expression and IL‑1β secretion in pacing HL‑1 cells via the NF‑κB/STAT3 signaling pathway, limiting the shorter APD caused by rapid pacing.

Focus on the Role of Inflammation as a Bridge between Ferroptosis and Atrial Fibrillation: A Narrative Review and Novel Perspective

In this comprehensive review, we examine the intricate interplay between inflammation, ferroptosis, and atrial fibrillation (AF), highlighting their significant roles in AF pathophysiology and pathogenesis. Augmented inflammatory responses are pivotal to AF, potentially leading to atrial remodeling and reentry phenomena by impacting calcium channels and atrial tissue fibrosis. A strong correlation exists between inflammatory cytokines and AF, underscoring the importance of inflammatory signaling pathways, such as NOD-like receptor thermal protien domain associated protein 3 (NLRP3) inflammasome, Nuclear Factor kappa B (NF- κ B) signaling, and Tumor necrosis factor- α (TNF- α ) signaling in AF development. Ferroptosis, a non-apoptotic regulated mode of cell death, has been widely studied in relation to cardiovascular diseases including heart failure, myocardial infarction, cardiomyopathy, and reperfusion injury. The interaction between ferroptosis and inflammation is complex and mutually influential. While significant progress has been made in understanding the inflammation-AF relationship, the role of inflammation as a conduit linking ferroptosis and AF remains underexplored. The specific pathogenesis and key molecules of atrial fibrosis caused by ferroptosis are still not fully understood. Here we review the role of inflammatory signaling in ferroptosis and AF. We elucidated the association between ferroptosis and AF, aiming to unveil mechanisms for targeted inhibition of atrial cell fibrosis and to propose novel therapeutic strategies for AF. This exploration is vital for advancing our knowledge and developing more effective interventions for AF, a condition deeply intertwined with inflammatory processes and ferroptotic pathways.

Ferroptosis mechanisms and regulations in cardiovascular diseases in the past, present, and future

Cardiovascular diseases (CVDs) are the main diseases that endanger human health, and their risk factors contribute to high morbidity and a high rate of hospitalization. Cell death is the most important pathophysiology in CVDs. As one of the cell death mechanisms, ferroptosis is a new form of regulated cell death (RCD) that broadly participates in CVDs (such as myocardial infarction, heart transplantation, atherosclerosis, heart failure, ischaemia/reperfusion (I/R) injury, atrial fibrillation, cardiomyopathy (radiation-induced cardiomyopathy, diabetes cardiomyopathy, sepsis-induced cardiac injury, doxorubicin-induced cardiac injury, iron overload cardiomyopathy, and hypertrophic cardiomyopathy), and pulmonary arterial hypertension), involving in iron regulation, metabolic mechanism and lipid peroxidation. This article reviews recent research on the mechanism and regulation of ferroptosis and its relationship with the occurrence and treatment of CVDs, aiming to provide new ideas and treatment targets for the clinical diagnosis and treatment of CVDs by clarifying the latest progress in CVDs research.

Upregulated Genes in Atrial Fibrillation Blood and the Left Atrium

INTRODUCTION

Atrial fibrillation (AF) is a common arrhythmia associated with aging. Many known risk factors are associated with AF, but many senior individuals do not develop AF despite having multiple risk factors. This finding suggests that other factors may be involved in AF onset. This study aimed to identify upregulated genes in the peripheral blood and left atrium of patients with AF. These genes may serve as potential biomarkers to predict AF onset risk and its complications.

METHODS

Gene expression data were analyzed from blood (n = 3) and left atrial samples (n = 15) of patients with AF and sinus rhythm. We evaluated the significant genes identified using p value analysis of weighted average difference to confirm their rankings. We created figures for the genes using GeneMANIA and performed a functional analysis using Cytoscape3.10.1. Hub and bottleneck genes were identified based on degree and betweenness centrality. We used reference expression (RefEx) to confirm the organs in which the extracted genes were expressed. Heatmaps and Gene ontology term evaluation were performed to further elucidate the biological functions of the genes.

RESULTS

We identified 12 upregulated genes (CAST, ASAH1, MAFB, VCAN, DDIT4, FTL, HEXB, PROS1, BNIP3L, PABPC1, YBX3, and S100A6) in both the blood and left atrium of patients with AF. We analyzed the gene functions using GeneMANIA and Cytoscape. The identified genes were involved in a variety of pathways, including lysosomal function and lipid and sphingolipid catabolism. Next, we investigated whether the 12 identified genes identified were systemically expressed or had high organ specificity. Finally, RefEx was used to analyze the gene expression levels in various tissues. Four genes, FTL, ASAH1, S100A6, and PABPC1, were highly expressed in the normal heart tissue. Finally, we evaluated the expression levels of the 12 genes in the blood of patients with AF using a heatmap. Our findings suggest that the 12 genes identified in this study, especially the lysosome-related genes (FTL and ASAH1), may be involved in AF pathogenesis.

CONCLUSION

Lysosome-related genes may be important to understand the AF pathophysiology and to develop AF-related future studies.

Advances in Ferroptosis-Inducing Agents by Targeted Delivery System in Cancer Therapy

Currently, cancer remains one of the most significant threats to human health. Treatment of most cancers remains challenging, despite the implementation of diverse therapies in clinical practice. In recent years, research on the mechanism of ferroptosis has presented novel perspectives for cancer treatment. Ferroptosis is a regulated cell death process caused by lipid peroxidation of membrane unsaturated fatty acids catalyzed by iron ions. The rapid development of bio-nanotechnology has generated considerable interest in exploiting iron-induced cell death as a new therapeutic target against cancer. This article provides a comprehensive overview of recent advancements at the intersection of iron-induced cell death and bionanotechnology. In this respect, the mechanism of iron-induced cell death and its relation to cancer are summarized. Furthermore, the feasibility of a nano-drug delivery system based on iron-induced cell death for cancer treatment is introduced and analyzed. Secondly, strategies for inducing iron-induced cell death using nanodrug delivery technology are discussed, including promoting Fenton reactions, inhibiting glutathione peroxidase 4, reducing low glutathione levels, and inhibiting system Xc-. Additionally, the article explores the potential of combined treatment strategies involving iron-induced cell death and bionanotechnology. Finally, the application prospects and challenges of iron-induced nanoagents for cancer treatment are discussed.

Ferroptosis-related exosomal non-coding RNAs: promising targets in pathogenesis and treatment of non-malignant diseases

Ferroptosis, an iron-dependent form of programmed cell death, introduces a novel perspective on cellular demise. This study investigates the regulatory network of exosomal non-coding RNAs (ncRNAs), including miRNAs, circRNAs, and lncRNAs, in ferroptosis modulation. The primary goal is to examine the pathological roles of ferroptosis-related exosomal ncRNAs, particularly in ischemic reperfusion injuries. The research reveals intricate molecular interactions governing the regulatory interplay between exosomal ncRNAs and ferroptosis, elucidating their diverse roles in different non-malignant pathological contexts. Attention is given to their impact on diseases, including cardiac, cerebral, liver, and kidney ischemic injuries, as well as lung, wound, and neuronal injuries. Beyond theoretical exploration, the study provides insights into potential therapeutic applications, emphasizing the significance of mesenchymal stem cells (MSCs)-derived exosomes. Findings underscore the pivotal role of MSC-derived exosomal ncRNAs in modulating cellular responses related to ferroptosis regulation, introducing a cutting-edge dimension. This recognition emphasizes the importance of MSC-derived exosomes as crucial mediators with broad therapeutic implications. Insights unveil promising avenues for targeted interventions, capitalizing on the diverse roles of exosomal ncRNAs, providing a comprehensive foundation for future therapeutic strategies.

Ferroptosis in organ fibrosis: From mechanisms to therapeutic medicines

Fibrosis occurs in many organs, and its sustained progress can lead to organ destruction and malfunction. Although numerous studies on organ fibrosis have been carried out, its underlying mechanism is largely unknown, and no ideal treatment is currently available. Ferroptosis is an iron-dependent process of programmed cell death that is characterized by lipid peroxidation. In the past decade, a growing body of evidence demonstrated the association between ferroptosis and fibrotic diseases, while targeting ferroptosis may serve as a potential therapeutic strategy. This review highlights recent advances in the crosstalk between ferroptosis and organ fibrosis, and discusses ferroptosis-targeted therapeutic approaches against fibrosis that are currently being explored.

Ferroptosis: a promising candidate for exosome-mediated regulation in different diseases

Ferroptosis is a newly discovered form of cell death that is featured in a wide range of diseases. Exosome therapy is a promising therapeutic option that has attracted much attention due to its low immunogenicity, low toxicity, and ability to penetrate biological barriers. In addition, emerging evidence indicates that exosomes possess the ability to modulate the progression of diverse diseases by regulating ferroptosis in damaged cells. Hence, the mechanism by which cell-derived and noncellular-derived exosomes target ferroptosis in different diseases through the system Xc-/GSH/GPX4 axis, NAD(P)H/FSP1/CoQ10 axis, iron metabolism pathway and lipid metabolism pathway associated with ferroptosis, as well as its applications in liver disease, neurological diseases, lung injury, heart injury, cancer and other diseases, are summarized here. Additionally, the role of exosome-regulated ferroptosis as an emerging repair mechanism for damaged tissues and cells is also discussed, and this is expected to be a promising treatment direction for various diseases in the future. Video Abstract.

Ferroptosis in cardiovascular diseases: role and mechanism

In multicellular organisms, regulatory cell death is a crucial aspect of growth and development. Ferroptosis, which was postulated roughly ten years ago, is a mode of cell death that differs from apoptosis, autophagy, and pyrodeath. This distinct pattern of cell death is triggered by an imbalance between oxidants and antioxidants and strongly associated with the metabolism of iron, lipids, amino acids, and glutathione. A growing body of research has implicated ferroptosis in the incidence and progression of many organ traumas and degenerative diseases. Recently, ferroptosis has gained attention as a crucial regulatory mechanism underlying the initiation and development of a variety of cardiovascular diseases, including myocardial ischemia/reperfusion injury, cardiomyopathy, arrhythmia, chemotherapy, and Corona Virus-2-induced cardiac injury. Pharmacological therapies that inhibit ferroptosis have great potential for the management of cardiovascular disorders. This review discusses the prevalence and regulatory mechanisms of ferroptosis, effect of ferroptosis on the immune system, significance of ferroptosis in cardiovascular diseases, and potential therapeutic value of regulating ferroptosis in a variety of heart diseases.

The correlation between gut microbiome and atrial fibrillation: pathophysiology and therapeutic perspectives

Regulation of gut microbiota and its impact on human health is the theme of intensive research. The incidence and prevalence of atrial fibrillation (AF) are continuously escalating as the global population ages and chronic disease survival rates increase; however, the mechanisms are not entirely clarified. It is gaining awareness that alterations in the assembly, structure, and dynamics of gut microbiota are intimately engaged in the AF progression. Owing to advancements in next-generation sequencing technologies and computational strategies, researchers can explore novel linkages with the genomes, transcriptomes, proteomes, and metabolomes through parallel meta-omics approaches, rendering a panoramic view of the culture-independent microbial investigation. In this review, we summarized the evidence for a bidirectional correlation between AF and the gut microbiome. Furthermore, we proposed the concept of "gut-immune-heart" axis and addressed the direct and indirect causal roots between the gut microbiome and AF. The intricate relationship was unveiled to generate innovative microbiota-based preventive and therapeutic interventions, which shed light on a definite direction for future experiments.

A review on microRNA detection and expression studies in dogs

MicroRNAs (miRNAs) are small non-coding RNAs that function by post-transcriptional regulation of gene expression. Their stability and abundance in tissue and body fluids makes them promising potential tools for both the diagnosis and prognosis of diseases and attractive therapeutic targets in humans and dogs. Studies of miRNA expression in normal and disease processes in dogs are scarce compared to studies published on miRNA expression in human disease. In this literature review, we identified 461 peer-reviewed papers from database searches using the terms "canine," "dog," "miRNA," and "microRNA"; we screened 244 for inclusion criteria and then included a total of 148 original research peer-reviewed publications relating to specific miRNA expression in canine samples. We found an overlap of miRNA expression changes between the four groups evaluated (normal processes, non-infectious and non-inflammatory conditions, infectious and/or inflammatory conditions, and neoplasia) in 39 miRNAs, 83 miRNAs in three of the four groups, 110 miRNAs in two of the three groups, where 158 miRNAs have only been reported in one of the groups. Additionally, the mechanism of action of these overlapping miRNAs varies depending on the disease process, elucidating a need for characterization of the mechanism of action of each miRNA in each disease process being evaluated. Herein we also draw attention to the lack of standardization of miRNA evaluation, consistency within a single evaluation method, and the need for standardized methods for a direct comparison.

Ferroptosis: a new strategy for cardiovascular disease

Cardiovascular disease (CVD) is currently one of the prevalent causes of human death. Iron is one of the essential trace elements in the human body and a vital component of living tissues. All organ systems require iron for various metabolic processes, including myocardial and skeletal muscle metabolism, erythropoiesis, mitochondrial function, and oxygen transport. Its deficiency or excess in the human body remains one of the nutritional problems worldwide. The total amount of iron in a normal human body is about 3-5 g. Iron deficiency may cause symptoms such as general fatigue, pica, and nerve deafness, while excessive iron plays a crucial role in the pathophysiological processes of the heart through ferroptosis triggered by the Fenton reaction. It differs from other cell death modes based on its dependence on the accumulation of lipid peroxides and REDOX imbalance, opening a new pathway underlying the pathogenesis and mechanism of CVDs. In this review, we describe the latest research progress on the mechanism of ferroptosis and report its crucial role and association with miRNA in various CVDs. Finally, we summarise the potential therapeutic value of ferroptosis-related drugs or ferroptosis inhibitors in CVDs.

Effects of Inflammatory Cell Death Caused by Catheter Ablation on Atrial Fibrillation

Atrial fibrillation (AF) poses a serious healthcare burden on society due to its high morbidity and the resulting serious complications such as thrombosis and heart failure. The principle of catheter ablation is to achieve electrical isolation by linear destruction of cardiac tissue, which makes AF a curable disease. Currently, catheter ablation does not have a high long-term success rate. The current academic consensus is that inflammation and fibrosis are central mechanisms in the progression of AF. However, artificially caused inflammatory cell death by catheter ablation may have a significant impact on structural and electrical remodeling, which may affect the long-term prognosis. This review first focused on the inflammatory response induced by apoptosis, necrosis, necroptosis, pyroptosis, ferroptosis and their interaction with arrhythmia. Then, we compared the differences in cell death induced by radiofrequency ablation, cryoballoon ablation and pulsed-field ablation. Finally, we discussed the structural and electrical remodeling caused by inflammation and the association between inflammation and the recurrence of AF after catheter ablation. Collectively, pulsed-field ablation will be a revolutionary innovation with faster, safer, better tissue selectivity and less inflammatory response induced by apoptosis-dominated cell death.

KCa3.1 Promotes Proinflammatory Exosome Secretion by Activating AKT/Rab27a in Atrial Myocytes during Rapid Pacing

Purpose

The aim of this study was to investigate the role of the medium-conductance calcium-activated potassium channel (KCNN4, KCa3.1) in the secretion of proinflammatory exosomes by atrial myocytes.

Methods

Eighteen beagles were randomly divided into the sham group (n = 6), pacing group (n = 6), and pacing+TRAM-34 group (n = 6). Electrophysiological data, such as the effective refractory period, atrial fibrillation (AF) induction, and AF duration, were collected by programmed stimulation. Atrial tissues were subjected to hematoxylin and eosin, Masson's trichrome, and immunofluorescence staining. The expression of KCa3.1 and Rab27a was assessed by immunohistochemistry and western blotting. The downstream signaling pathways involved in KCa3.1 were examined by rapid pacing or overexpressing KCNN4 in HL-1 cells.

Results

Atrial rapid pacing significantly induced electrical remodeling, inflammation, fibrosis, and exosome secretion in the canine atrium, while TRAM-34 (KCa3.1 blocker) inhibited these changes. Compared with those in control HL-1 cells, the levels of exosome markers and inflammatory factors were increased in pacing HL-1 cells. Furthermore, the levels of CD68 and iNOS in macrophages incubated with exosomes derived from HL-1 cells were higher in the pacing-exo group than in the control group. More importantly, KCa3.1 regulated exosome secretion through the AKT/Rab27a signaling pathway. Similarly, inhibiting the downstream signaling pathway of KCa3.1 significantly inhibited exosome secretion.

Conclusions

KCa3.1 promotes proinflammatory exosome secretion through the AKT/Rab27a signaling pathway. Inhibiting the KCa3.1/AKT/Rab27a signaling pathway reduces myocardial tissue structural remodeling in AF.

The role of microRNAs in ferroptosis

Ferroptosis is a newly discovered type of programmed cell death, which is closely related to the imbalance of iron metabolism and oxidative stress. Ferroptosis has become an important research topic in the fields of cardiomyopathy, tumors, neuronal injury disorders, and ischemia perfusion disorders. As an important part of non-coding RNA, microRNAs regulate various metabolic pathways in the human body at the post-transcriptional level and play a crucial role in the occurrence and development of many diseases. The present review introduces the mechanisms of ferroptosis and describes the relevant pathways by which microRNAs affect cardiomyopathy, tumors, neuronal injury disorders and ischemia perfusion disorders through regulating ferroptosis. In addition, it provides important insights into ferroptosis-related microRNAs, aiming to uncover new methods for treatment of the above diseases, and discusses new ideas for the implementation of possible microRNA-based ferroptosis-targeted therapies in the future.