Effect and Mechanism of LRP6 on Cardiac Myocyte Ferroptosis in Myocardial Infarction

Endonuclear Circ-calm4 regulates ferroptosis via a circR-Loop of the COMP gene in pulmonary artery smooth muscle cells

Pulmonary hypertension (PH) is a serious pulmonary vascular disease characterized by vascular remodeling. Circular RNAs (CircRNAs) play important roles in pulmonary hypertension, but the mechanism of PH is not fully understood, particularly the roles of circRNAs located in the nucleus. Circ-calmodulin 4 (circ-calm4) is expressed in both the cytoplasm and the nucleus of pulmonary arterial smooth muscle cells (PASMCs). This study aimed to investigate the role of endonuclear circ-calm4 in PH and elucidate its underlying signaling pathway in ferroptosis. Immunoblotting, quantitative real-time polymerase chain reaction (PCR), malondialdehyde (MDA) assay, immunofluorescence, iron assay, dot blot, and chromatin immunoprecipitation (ChIP) were performed to investigate the role of endonuclear circ-calm4 in PASMC ferroptosis. Increased endonuclear circ-calm4 facilitated ferroptosis in PASMCs under hypoxic conditions. We further identified the cartilage oligomeric matrix protein (COMP) as a downstream effector of circ-calm4 that contributed to the occurrence of hypoxia-induced ferroptosis in PASMCs. Importantly, we confirmed that endonuclear circ-calm4 formed circR-loops with the promoter region of the COMP gene and negatively regulated its expression. Inhibition of COMP restored the phenotypes related to ferroptosis under hypoxia stimulation combined with antisense oligonucleotide (ASO)-circ-calm4 treatment. We conclude that the circ-calm4/COMP axis contributed to hypoxia-induced ferroptosis in PASMCs and that circ-calm4 formed circR-loops with the COMP promoter in the nucleus and negatively regulated its expression. The circ-calm4/COMP axis may be useful for the design of therapeutic strategies for protecting cellular functionality against ferroptosis and pulmonary hypertension.

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.

Upregulation of Serum miR-132 and miR-152 in Vietnamese Patients with Heart Failure

Background

MicroRNAs (miRs) are emerging targets for the diagnosis, prognosis and treatment of heart failure (HF). Accumulated evidence showed that microRNA-132 (miR-132) and microRNA-152 (miR-152) play critical roles in the development of multiple pathological processes of the heart. Although their upregulations have been detected in the failing hearts of humans and animal models, little is known about the circulating levels of miR-132 and miR-152 in patients with HF.

Methods

Our study was conducted from January 2022 to August 2022 at the Cardiology Department of the University Medical Center in Ho Chi Minh City, Vietnam. During study period, 36 participants were consecutively enrolled, including 18 HF patients and 18 patients who age and sex matched the non-HF controls. Serum samples of study participants were collected on admission and the expression levels of miR-132 and miR-152 were measured by quantitative reverse transcription polymerase chain reaction (RT-PCR). The comparative cycle threshold method (ΔCt) was applied to calculate the relative expression of miRs.

Results

The miR concentration in HF group was significantly lower than that in the control group. In contrast, the serum levels of miR-132 and miR-152 were significantly higher in HF patients. Further analyses of receiver operating characteristic (ROC) curve showed that miR-132 and miR-152 individually had moderate diagnostic potential for HF (with area under curve [AUC] values of 0.713 and 0.698, respectively). A positive correlation between these miRs was also confirmed.

Conclusion

Serum miR-132 and miR-152 were upregulated in Vietnamese patients with HF and may serve as candidate biomarkers for diagnostic purposes.

Decoding ferroptosis: Revealing the hidden assassin behind cardiovascular diseases

The discovery of regulatory cell death processes has driven innovation in cardiovascular disease (CVD) therapeutic strategies. Over the past decade, ferroptosis, an iron-dependent form of regulated cell death driven by excessive lipid peroxidation, has been shown to drive the development of multiple CVDs. This review provides insights into the evolution of the concept of ferroptosis, the similarities and differences with traditional modes of programmed cell death (e.g., apoptosis, autophagy, and necrosis), as well as the core regulatory mechanisms of ferroptosis (including cystine/glutamate transporter blockade, imbalance of iron metabolism, and lipid peroxidation). In addition, it provides not only a detailed review of the role of ferroptosis and its therapeutic potential in widely studied CVDs such as coronary atherosclerotic heart disease, myocardial infarction, myocardial ischemia/reperfusion injury, heart failure, cardiomyopathy, and aortic aneurysm but also an overview of the phenomenon and therapeutic perspectives of ferroptosis in lesser-addressed CVDs such as cardiac valvulopathy, pulmonary hypertension, and sickle cell disease. This article aims to integrate this knowledge to provide a comprehensive view of ferroptosis in a wide range of CVDs and to drive innovation and progress in therapeutic strategies in this field.

Anti-Ferroptotic Treatment Deteriorates Myocardial Infarction by Inhibiting Angiogenesis and Altering Immune Response

Mammalian cardiomyocytes have limited regenerative ability. Cardiac disease, such as congenital heart disease and myocardial infarction, causes an initial loss of cardiomyocytes through regulated cell death (RCD). Understanding the mechanisms that govern RCD in the injured myocardium is crucial for developing therapeutics to promote heart regeneration. We previously reported that ferroptosis, a non-apoptotic and iron-dependent form of RCD, is the main contributor to cardiomyocyte death in the injured heart. To investigate the mechanisms underlying the preference for ferroptosis in cardiomyocytes, we examined the effects of anti-ferroptotic reagents in infarcted mouse hearts. The results revealed that the anti-ferroptotic reagent did not improve neonatal heart regeneration, and further compromised the cardiac function of juvenile hearts. On the other hand, ferroptotic cardiomyocytes played a supportive role during wound healing by releasing pro-angiogenic factors. The inhibition of ferroptosis in the regenerating mouse heart altered the immune and angiogenic responses. Our study provides insights into the preference for ferroptosis over other types of RCD in stressed cardiomyocytes, and guidance for designing anti-cell-death therapies for treating heart disease.

Therapeutic exploitation of ferroptosis

Pathological breakdown of membrane lipids through excessive lipid peroxidation (LPO) was first described in the mid-20th century and is now recognized as a form of regulated cell death, dubbed ferroptosis. Accumulating evidence unveils how metabolic regulation restrains peroxidation of phospholipids within cellular membranes, thereby impeding ferroptosis execution. Unleashing these metabolic breaks is currently therapeutically explored to sensitize cancers to ferroptosis inducing anti-cancer therapies. Reversely, these natural ferroptotic defense mechanisms can fail resulting in pathological conditions or diseases such as ischemia-reperfusion injury, multi-organ dysfunction, stroke, infarction, or neurodegenerative diseases. This minireview outlines current ferroptosis-inducing anti-cancer strategies and highlights the detection as well as the therapeutic targeting of ferroptosis in preclinical experimental settings. Herein, we also briefly summarize observations related to LPO, iron and redox deregulation in patients that might hint towards ferroptosis as a contributing factor.

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.

Serum circPRDM5 as a novel diagnostic biomarker for acute myocardial infarction

BACKGROUND

Circular RNA (CircRNA) is known to play an important role in cardiovascular diseases, but its use as a biomarker of acute myocardial infarction (AMI) has not been studied. This study explores the feasibility of circPRDM5 as a novel biomarker of AMI.

METHODS

CircPRDM5 was screened by bioinformatics, the correct circPRDM5 primers were tested by agarose gel electrophoresis (AGE) and Sanger sequencing, and the expression level of serum circPRDM5 was detected by Quantitative Reverse Transcription-Polymerase Chain Reaction. (qRT-PCR), and the diagnostic value of circPRDM5 was analyzed by the receiver operating characteristic (ROC) curve.

RESULTS

The expression of circPRDM5 in serum of AMI patients was significantly decreased compared with that of healthy control group and angina group (P < 0.001). The area under ROC curve of serum circPRDM5 was 0.862 [95 % CI, 0.814-0.909]. The combined diagnosis of serum circPRDM5, cardiac troponin T (cTnT) and creatine kinase-MB (CK-MB) could improve the sensitivity of diagnosing AMI. The expression level of serum circPRDM5 increased after percutaneous coronary intervention (PCI).

CONCLUSIONS

CircPRDM5 can be used as a novel biomarker for AMI, and its combination with cTnT and CK-MB can improve diagnostic value.

The potential role and mechanism of circRNAs in Ferroptosis: A comprehensive review

Cell death encompasses various mechanisms, including necrosis and apoptosis. Ferroptosis, a unique form of regulated cell death, emerged as a non-apoptotic process reliant on iron and reactive oxygen species (ROS). Distinguishing itself from other forms of cell death, ferroptosis exhibits distinct morphological, biochemical, and genetic features. Circular RNAs (circRNAs), a novel class of RNA molecules, play crucial regulatory roles in ferroptosis-mediated pathways and cellular processes. With their circular structure and stability, circRNAs function as microRNA sponges and participate in protein regulation, offering diverse mechanisms for cellular control. Accumulating evidence indicates that circRNAs are key players in diseases associated with ferroptosis, presenting opportunities for diagnostic and therapeutic applications. This study explores the regulatory roles of circRNAs in ferroptosis and their potential in diseases such as cancer, neurological disorders, and cardiovascular diseases. By investigating the relationship between circRNAs and ferroptosis, this research provides new insights into the diagnosis, treatment, and prognosis of ferroptosis-related diseases. Furthermore, the therapeutic implications of targeting circRNAs in cancer treatment and the modulation of ferroptosis pathways demonstrate the potential of circRNAs as diagnostic markers and therapeutic targets. Overall, understanding the involvement of circRNAs in regulating ferroptosis opens up new avenues for advancements in disease management.

Ferroptosis, a Regulated Form of Cell Death, as a Target for the Development of Novel Drugs Preventing Ischemia/Reperfusion of Cardiac Injury, Cardiomyopathy and Stress-Induced Cardiac Injury

The hospital mortality in patients with ST-segment elevation myocardial infarction (STEMI) is about 6% and has not decreased in recent years. The leading cause of death of these patients is ischemia/reperfusion (I/R) cardiac injury. It is quite obvious that there is an urgent need to create new drugs for the treatment of STEMI based on knowledge about the pathogenesis of I/R cardiac injury, in particular, based on knowledge about the molecular mechanism of ferroptosis. In this study, it was demonstrated that ferroptosis is involved in the development of I/R cardiac injury, antitumor drug-induced cardiomyopathy, diabetic cardiomyopathy, septic cardiomyopathy, and inflammation. There is indirect evidence that ferroptosis participates in stress-induced cardiac injury. The activation of AMPK, PKC, ERK1/2, PI3K, and Akt prevents myocardial ferroptosis. The inhibition of HO-1 alleviates myocardial ferroptosis. The roles of GSK-3β and NOS in the regulation of ferroptosis require further study. The stimulation of Nrf2, STAT3 prevents ferroptosis. The activation of TLR4 and NF-κB promotes ferroptosis of cardiomyocytes. MiR-450b-5p and miR-210-3p can increase the tolerance of cardiomyocytes to hypoxia/reoxygenation through the inhibition of ferroptosis. Circ_0091761 RNA, miR-214-3p, miR-199a-5p, miR-208a/b, miR-375-3p, miR-26b-5p and miR-15a-5p can aggravate myocardial ferroptosis.

CircRNA and ferroptosis in human disease: Insights for new treatments

Circular RNA (circRNA), classified as a type of non-coding RNA, has gained significant attention in the field of biology due to its distinctive ring structure and functional properties. Recent research has provided evidence that specific circRNAs have the ability to modulate disease progression through diverse mechanisms, one of which is by regulating cellular ferroptosis. Ferroptosis is a form of regulated cell death that is driven by iron dependency and lipid peroxidation, and extensive investigations have revealed a relationship between ferroptosis and disease development. In addition to evidence that both circRNAs and ferroptosis exert critical roles in disease progression, circRNAs have also been shown to actively mediate the process of ferroptosis. The relationship between circRNAs and ferroptosis therefore influences disease progression and offers novel targets for disease treatment. By directly or indirectly modulating the expression of circRNAs that regulate the expression of ferroptosis-related proteins, it may be possible to impact disease progression by promoting or inhibiting ferroptosis. Current research indicates such approaches may hold significant value in a wide variety of common diseases across physiological systems. This review comprehensively summarizes the findings of recent studies investigating the roles of circRNAs in the regulation of ferroptosis in various diseases.

The mechanism of ferroptosis and its related diseases

Ferroptosis, a regulated form of cellular death characterized by the iron-mediated accumulation of lipid peroxides, provides a novel avenue for delving into the intersection of cellular metabolism, oxidative stress, and disease pathology. We have witnessed a mounting fascination with ferroptosis, attributed to its pivotal roles across diverse physiological and pathological conditions including developmental processes, metabolic dynamics, oncogenic pathways, neurodegenerative cascades, and traumatic tissue injuries. By unraveling the intricate underpinnings of the molecular machinery, pivotal contributors, intricate signaling conduits, and regulatory networks governing ferroptosis, researchers aim to bridge the gap between the intricacies of this unique mode of cellular death and its multifaceted implications for health and disease. In light of the rapidly advancing landscape of ferroptosis research, we present a comprehensive review aiming at the extensive implications of ferroptosis in the origins and progress of human diseases. This review concludes with a careful analysis of potential treatment approaches carefully designed to either inhibit or promote ferroptosis. Additionally, we have succinctly summarized the potential therapeutic targets and compounds that hold promise in targeting ferroptosis within various diseases. This pivotal facet underscores the burgeoning possibilities for manipulating ferroptosis as a therapeutic strategy. In summary, this review enriched the insights of both investigators and practitioners, while fostering an elevated comprehension of ferroptosis and its latent translational utilities. By revealing the basic processes and investigating treatment possibilities, this review provides a crucial resource for scientists and medical practitioners, aiding in a deep understanding of ferroptosis and its effects in various disease situations.

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.

Non-coding RNA-mediated modulation of ferroptosis in cardiovascular diseases

Cardiovascular disease (CVD) is a major contributor to increasing morbidity and mortality worldwide and seriously threatens human health and life. Cardiomyocyte death is considered the pathological basis of various CVDs, including myocardial infarction, heart failure, and aortic dissection. Multiple mechanisms, such as ferroptosis, necrosis, and apoptosis, contribute to cardiomyocyte death. Among them, ferroptosis is an iron-dependent form of programmed cell death that plays a vital role in various physiological and pathological processes, from development and aging to immunity and CVD. The dysregulation of ferroptosis has been shown to be closely associated with CVD progression, yet its underlying mechanisms are still not fully understood. In recent years, a growing amount of evidence suggests that non-coding RNAs (ncRNAs), particularly microRNAs, long non-coding RNAs, and circular RNAs, are involved in the regulation of ferroptosis, thus affecting CVD progression. Some ncRNAs also exhibit potential value as biomarker and/or therapeutic target for patients with CVD. In this review, we systematically summarize recent findings on the underlying mechanisms of ncRNAs involved in ferroptosis regulation and their role in CVD progression. We also focus on their clinical applications as diagnostic and prognostic biomarkers as well as therapeutic targets in CVD treatment. DATA AVAILABILITY: No new data were created or analyzed in this study. Data sharing is not applicable to this article.

Circular RNAs in ferroptosis: regulation mechanism and potential clinical application in disease

Ferroptosis, an iron-dependent non-apoptotic form of cell death, is reportedly involved in the pathogenesis of various diseases, particularly tumors, organ injury, and degenerative pathologies. Several signaling molecules and pathways have been found to be involved in the regulation of ferroptosis, including polyunsaturated fatty acid peroxidation, glutathione/glutathione peroxidase 4, the cysteine/glutamate antiporter system Xc-, ferroptosis suppressor protein 1/ubiquinone, and iron metabolism. An increasing amount of evidence suggests that circular RNAs (circRNAs), which have a stable circular structure, play important regulatory roles in the ferroptosis pathways that contribute to disease progression. Hence, ferroptosis-inhibiting and ferroptosis-stimulating circRNAs have potential as novel diagnostic markers or therapeutic targets for cancers, infarctions, organ injuries, and diabetes complications linked to ferroptosis. In this review, we summarize the roles that circRNAs play in the molecular mechanisms and regulatory networks of ferroptosis and their potential clinical applications in ferroptosis-related diseases. This review furthers our understanding of the roles of ferroptosis-related circRNAs and provides new perspectives on ferroptosis regulation and new directions for the diagnosis, treatment, and prognosis of ferroptosis-related diseases.

Plasma exosomes from patients with acute myocardial infarction alleviate myocardial injury by inhibiting ferroptosis through miR-26b-5p/SLC7A11 axis

AIMS

Ferroptosis promotes myocardial injury in acute myocardial infarction (AMI). Increasing evidence suggests the crucial role of exosomes in post-AMI pathophysiological regulation. We aimed to investigate the effects and underlying mechanisms of plasma exosomes derived from patients with AMI in inhibiting ferroptosis after AMI.

METHODS

Plasma exosomes were isolated from controls (Con-Exo) and patients with AMI (MI-Exo). These exosomes were incubated with hypoxic cardiomyocytes or intramyocardially injected into the AMI mice. Histopathological changes, cell viability, and cell death were measured to evaluate the myocardial injury. For the ferroptosis evaluation, iron particle deposition, Fe²⁺, ROS, MDA, GSH, and GPX4 levels were detected. Exosomal miR-26b-5p expression was detected by qRT-PCR, and the targeting relationship between miR-26b-5p and SLC7A11 was confirmed by dual luciferase reporter gene assay. The role of the miR-26b-5p/SLC7A11 axis in the regulation of ferroptosis was validated by rescue experiments in cardiomyocytes.

FINDINGS

Hypoxia-treatment induced ferroptosis and injury in H9C2 cells and primary cardiomyocytes. MI-Exo performed better than Con-Exo in inhibiting hypoxia-induced ferroptosis. miR-26b-5p expression was downregulated in MI-Exo, and miR-26b-5p overexpression significantly eliminated the inhibitory effect of MI-Exo on ferroptosis. Mechanistically, knockdown of miR-26b-5p upregulated SLC7A11/GSH/GPX4 expressions by directly targeting SLC7A11. Moreover, SLC7A11 silencing also reversed the inhibitory effect of MI-Exo on hypoxia-induced ferroptosis. In vivo, MI-Exo significantly inhibited ferroptosis, reduced myocardial injury, and improved the cardiac function of AMI mice.

SIGNIFICANCE

Our findings revealed a novel mechanism of myocardial protection that downregulation of miR-26b-5p in MI-Exo notably upregulated SLC7A11 expression, thereby inhibiting post-AMI ferroptosis and alleviating myocardial injury.

LRP6-mediated phosphorylation of connexin43 in myocardial infarction

Ventricular tachycardia (VT) and ventricular fibrillation are most causes of early death in patients with acute myocardial infarction (AMI). Conditional cardiac-specific low-density lipoprotein receptor-related protein 6 (LRP6)-knockout mice with connexin 43 (Cx43) reduction triggered the lethal ventricular arrhythmias. Thus, it is necessary for exploring whether LRP6 and its upstream genes circRNA1615 mediate the phosphorylation of Cx43 in VT of AMI. Here, we showed that circRNA1615 regulated the expression of LRP6 mRNA through sponge adsorption of miR-152-3p. Importantly, LRP6 interference fragments aggravated hypoxia injury of Cx43, while overexpression of LRP6 improved the phosphorylation of Cx43. Subsequently, interference with G-protein alpha subunit (Gα_s) downstream of LRP6 further inhibited the phosphorylation of Cx43, along with increasing VT. Our results demonstrated that LRP6 upstream genes circRNA1615 controlled the damage effect and VT in AMI, and LRP6 mediated the phosphorylation of Cx43 via Gα_s which played a role in VT of AMI.

Idebenone attenuates ferroptosis by inhibiting excessive autophagy via the ROS-AMPK-mTOR pathway to preserve cardiac function after myocardial infarction

Cardiovascular diseases (CVDs) are the leading causes of mortality worldwide. As a type of CVDs, myocardial infarction (MI) induces ischemia hypoxia, which leads to excessive reactive oxygen species (ROS), resulting in multiple cell deaths and contributing to the subsequent development of heart failure or premature death. Recent evidence indicates that ROS-induced lipid peroxidation promotes autophagy and ferroptosis, leading to the loss of healthy myocardium and resulting in the dysfunction of cardiac tissue. Theoretically, cardiac function would be preserved after MI by inhibiting autophagy and ferroptosis. As an analog of coenzyme Q10 (CoQ10) and a clinically approved drug, idebenone would be used to inhibit ferroptosis and preserve cardiac function due to its capacity to improve mitochondrial physiology with antioxidant and anti-inflammatory properties. Here, we confirmed that the addition of idebenone inhibited H₂O₂-induced and RSL3-induced ferroptosis. Furthermore, the ROS-AMPK-mTOR pathway axis was identified as the signaling pathway that idebenone stimulated to prevent excessive autophagy and consequent ferroptosis. In the MI animal model, idebenone demonstrated a cardioprotective role by regulating ROS-dependent autophagy and inhibiting ferroptosis, which paves the way for the future clinical translation of idebenone in MI management.

Adaptor protein HIP-55-mediated signalosome protects against ferroptosis in myocardial infarction

Ischemic heart disease is a leading cause of death worldwide. Myocardial infarction (MI) results in cardiac damage due to cell death and insufficient cardiomyocyte self-renewal. Ferroptosis, a novel type of cell death, has recently been shown as a key cause of cardiomyocyte death after MI. However, the complicated regulation mechanisms involved in ferroptosis, especially how ferroptosis is integrated into classical cell survival/death pathways, are still unclear. Here, we discovered that HIP-55, a novel adaptor protein, acts as a hub protein for the integration of the ferroptosis mechanism into the classical AKT cell survival and MAP4K1 cell death pathways for MI injury. The expression of HIP-55 is induced in MI. Genetic deletion of HIP-55 increased cardiomyocyte ferroptosis and MI injury, whereas cardiac-specific overexpression of HIP-55 significantly alleviated cardiomyocyte ferroptosis and MI injury. Mechanistically, HIP-55 was identified as a new AKT substrate. AKT phosphorylates HIP-55 at S269/T291 sites and further HIP-55 directs AKT signaling to negatively regulate the MAP4K1 pathway against MI injury in a site-specific manner. S269A/T291A-mutated HIP-55 (HIP-55AA), which is defective in AKT phosphorylation and significantly decreases the interaction between HIP-55 and MAP4K1, failed to inhibit the MAP4K1/GPX4 ferroptosis pathway. In line with this mechanism, cardiac-specific overexpression of HIP-55WT mice, but not cardiac-specific overexpression of HIP-55AA mice, protected cardiomyocytes against MI-induced ferroptosis and cardiac injury in vivo. These findings suggest that HIP-55 rewired the classical AKT (cell survival) and MAPK (cell death) pathways into ferroptosis mechanism in MI injury. HIP-55 may be a new therapeutic target for myocardial damage.

Klotho improves cardiac fibrosis, inflammatory cytokines, ferroptosis, and oxidative stress in mice with myocardial infarction

The anti-aging protein Klotho has been associated with cardiovascular health protection. Nevertheless, the protective mechanism remains unknown. The present study is aimed at exploring the effect of Klotho on cardiac remodeling and its potential mechanism in mice with myocardial infarction (MI). We used left anterior coronary artery descending ligation to develop an MI model for in vivo analyses. In contrast, H9C2 cells and cardiac fibroblasts were used to establish the oxygen-glucose deprivation (OGD) model in in vitro analyses. In vivo and in vitro models were treated with Klotho. Compound C, an AMPK signaling inhibitor, was used to determine whether Klotho's effects are mediated through the AMPK/mTOR signaling pathway. Echocardiography, Masson trichrome staining, immunofluorescence, immunohistochemistry, real-time polymerase chain reaction (RT-PCR), and western blot were used to detect the related indicators. The findings of the in vivo model indicate that Klotho treatment improved the mice's cardiac function, reduced cardiac fibrosis, and attenuated myocardial inflammatory factors, ferroptosis, and oxidative stress. The results of the in vitro model were in line with the findings of in vivo modeling. An AMPK inhibitor, Compound C, reversed all these effects. In conclusion, Klotho potentially improves cardiac remodeling in MI mice by regulating AMPK/mTOR signaling, demonstrating Klotho as an effective MI therapeutic agent.

MicroRNA152-3p Protects Against Ischemia/Reperfusion-Induced Bbb Destruction Possibly Targeting the MAP3K2/JNK/c-Jun Pathway

In the current study, we reported that overexpression of miR-152-3p effectively ameliorated neurological deficits and protected blood-brain barrier(BBB) integrity in middle cerebral artery occlusion (MCAO) rats. In an in vitro model, the level of miR-152-3p was significantly decreased in bEnd.3 cells after oxygen–glucose deprivation/reperfusion (OGD/R) insult. miR-152-3p overexpressing bEnd.3 cell monolayers were protected from OGD/R-induced microvascular hyperpermeability. The miR-152-3p-mediated protective effect was associated with lower apoptosis of endothelia by negatively modulating the MAP3K2/JNK/c-Jun pathway.

Protective effects of Salvianolic acid B on rat ferroptosis in myocardial infarction through upregulating the Nrf2 signaling pathway

Accumulating evidence has highlighted the role of ferroptosis, a novel type of programmed cell death involved in the pathological process of myocardial infarction (MI). However, the underlying mechanism of ferroptosis in mediating MI is complicated that needs to be further investigated. Salvianolic acid B (Sal B) extracted from the traditional Chinese medicine (TCM) herb Salvia miltiorrhiza possesses pharmacological function against MI, which provides us with a new direction to explore the effect of Sal B on ferroptosis after myocardial ischemic injury. In the present study, iron accumulation and expression levels of ferroptosis-related proteins in MI rats altered in a time-dependent manner. Importantly, treatment of ferroptosis inhibitors ferrostatin-1 (Fer-1) or deferoxamine (DFO) reversed typical changes of ferroptosis, including iron overload, lipid peroxide accumulation, mitochondrial damage, and specific expression levels of ferroptosis-related proteins, thereby alleviating myocardial injury in rats. Similar results were observed in Sal B-treated MI rats in a dose-dependent manner. In addition, NFE2-related factor 2 (Nrf2) was strongly activated by the treatment of Sal B. In vivo knockdown of Nrf2 in MI rats enhanced ferroptosis and damaged the protective effect of Sal B on MI. Furthermore, Sal B administration was unable to significantly reverse expression levels of target genes of Nrf2 that were associated with iron homeostasis and oxidative stress (e.g., HO-1, xCT, Gpx4, Fth1, and Fpn1) in MI rats after knockdown of Nrf2. Taken together, Sal B contributed to protecting MI by inhibiting ferroptosis via activating the Nrf2 signaling pathway.

CAV1 alleviated CaOx stones formation via suppressing autophagy-dependent ferroptosis

Background

Calcium oxalate (CaOx) is the most common type of kidney stone, but the mechanism of CaOx stones formation remains unclear. The injury of renal cells such as ferroptosis and autophagy has been considered a basis for stones formation.

Methods

We conducted transmission electron microscope (TEM), reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH), and C11-BODIPY analysis to explore whether CaOx could induce autophagy-dependent ferroptosis in vivo and in vitro. To explore the possible mechanism, we conducted bioinformatic analysis of patients with or without CaOx stones, Western blot and qPCR were used to identify the different genes we found in bioinformatic analysis.

Results

In our study, we found that CaOx could induce autophagy-dependent ferroptosis no matter in vivo or in vitro, which might finally lead to urolithiasis. Bioinformatic analysis of the GSE73680 dataset indicated that the expression of caveolin-1 (CAV1) was higher in control patients than CaOx stone patients, the STRING database indicated that CAV1 might interact with low density lipoprotein receptro-related protein 6 (LRP6), Gene Set Enrichment Analysis (GSEA) showed that the WNT pathway positively associated with the control group while negatively related to the stone group, and LRP6 was the core gene of the WNT pathway. Western blot found that CAV1, LRP6, and Wnt/β-Catenin were decreased in Human Kidney2 (HK2) cells stimulated with CaOx. Furthermore, the WNT pathway was considered to be involved in autophagy and ferroptosis.

Conclusions

We presumed that CAV1 could ameliorate autophagy-dependent ferroptosis through the LRP6/Wnt/β-Catenin axis, and finally alleviate CaOx stone formation.

LPIN1 Is a Regulatory Factor Associated With Immune Response and Inflammation in Sepsis

Objectives

Sepsis is a clinical disease that is typically treated in the intensive care unit, and the complex pathophysiology under this disease has not been thoroughly understood. While ferroptosis is involved in inflammation and infection, its effect in sepsis is still unknown. The study aimed to identify ferroptosis-related genes in sepsis, providing translational potential therapeutic targets.

Methods

The dataset GSE65682 was used to download the sample source from the Gene Expression Omnibus (GEO) database. Consensus weighted gene co-expression network analysis (WGCNA) was performed to find suspected modules of sepsis. The differentially expressed genes (DEGs) most significantly associated with mortality were intersected with those altered by lipopolysaccharide (LPS) treatment and were further analyzed for the identification of main pathways of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. The related pathway markers were further verified by qPCR.

Results

A total of 802 blood samples with sepsis were included for WGCNA, which identified 21 modules. Intersected with ferroptosis databases and LPS treatment groups, we identified two ferroptosis-related genes: PEBP1 and LPIN1. Only LPIN1 contributes to a poor outcome. Then, 205 DEGs were further identified according to the high or low LPIN1 expression. Among them, we constructed a gene regulatory network with several transcriptional factors using the NetworkAnalyst online tool and identified that these genes mostly correlate with inflammation and immune response. The immune infiltration analysis showed that lower expression of LPIN1 was related to macrophage infiltration and could be an independent predictor factor of the survival status in sepsis patients. Meanwhile, the multivariate Cox analysis showed that LPIN1 had a significant correlation with survival that was further verified by in vitro and in vivo experiments.

Conclusion

In conclusion, LPIN1 could become a reliable biomarker for patient survival in sepsis, which is associated with immune and inflammation status.