The correlation between ferroptosis and m6A methylation in patients with acute kidney injury

Methyltransferase-like 14 promotes ferroptosis in sepsis-induced acute kidney injury via increasing the m6A methylation modification of LPCAT3

Acute kidney injury (AKI) is one of the most serious and common complications in the course of sepsis, known for its poor prognosis and high mortality rate. Recently, ferroptosis, as a newly discovered regulatory cell death, might be closely associated with the progression of AKI. METTL14 is a writer of RNA m6A, an abundant epigenetic modification in transcriptome with broad function. Hence, the purpose of our study is to explore the potential function and mechanism of METTL14 on the ferroptosis in sepsis-induced AKI. In this paper, TCMK-1 cells and mice treated with LPS were used to constructe AKI model in vitro and in vivo. Pathological changes of renal tissue were observed by HE staining. The fluorescent probe C11-BODIPY and 4HNE kits were used to measure the lipid peroxidation. The ferroptosis index was evaluated by MDA, GSH and Fe2+ kits. The total m6A levels were analyzed by EpiQuik M6A RNA methylation kit, and the m6A levels of LPCAT3 were examined by Me-RIP assay. Finally, the interaction between LPCAT3 and METTL14 was clarified using RIP and dual-luciferase reporter gene assays. Our works revealed that the m6A level and ferroptosis was markedly ascended in LPS-induced TCMK-1 cells. The silence of METTL14 lowered the cell viability, the levels of MDA, Fe2+ and lipid peroxidation in the LPS-stimulated AKI model in vitro and in vivo, but increase GSH levels. Moreover, the up-regulation of ferroptosis-related proteins by LPS was notably inhibited by the knockdown of METTL14. In addition, silencing METTL14 reduced the m6A and mRNA levels of LPCAT3. Furthermore, the efficacy of METTL14 downregulation on the ferroptosis in the LPS-induced TCMK-1 cells were antagonized by LPCAT3 overexpression. Taken together, our findings revealed that METTL14 knockdown resisted ferroptosis in sepsis-induced AKI through lessening the level of LPCAT3 mediated by m6A modification.

FTO attenuates TNF-α-induced damage of proximal tubular epithelial cells in acute pancreatitis-induced acute kidney injury via targeting AQP3 in an N6-methyladenosine-dependent manner

BACKGROUND

Acute kidney injury (AKI) is a frequent complication of severe acute pancreatitis (SAP). Previous investigations have revealed the involvement of FTO alpha-ketoglutarate-dependent dioxygenase (FTO) and aquaporin 3 (AQP3) in AKI. Therefore, the aim of this study is to explore the association of FTO and AQP3 on proximal tubular epithelial cell damage in SAP-induced AKI.

METHODS

An in-vitro AKI model was established in human proximal tubular epithelial cells (PTECs) HK-2 via tumor necrosis factor-α (TNF-α) induction (20 ng/mL), after which FTO and AQP3 expression was manipulated and quantified by quantitative real-time PCR and Western blotting. The viability and apoptosis of PTECs under various conditions, and reactive oxygen species (ROS), superoxide dismutase (SOD), and malonaldehyde (MDA) levels within these cells were measured using commercial assay kits and flow cytometry. Methylated RNA immunoprecipitation and mRNA stability assays were performed to elucidate the mechanism of FTO-mediated N6-methyladenosine (m6A) modification. Western blotting was performed to quantify β-catenin protein levels in the PTECs.

RESULTS

FTO overexpression attenuated the TNF-α-induced decrease in viability and SOD levels, elevated apoptosis, increased levels of ROS and MDA, and diminished TNF-α-induced AQP3 expression and reduced β-catenin expression, but its silencing led to contradictory results. FTO negatively modulates AQP3 levels in RTECs in an m6A-depednent manner and compromises AQP3 stability. In addition, all FTO overexpression-induced effects in TNF-α-induced PTECs were neutralized following AQP3 upregulation.

CONCLUSION

FTO alleviates TNF-α-induced damage to PTECs in vitro by targeting AQP3 in an m6A-dependent manner.

m6A demethylase FTO transcriptionally activated by SP1 improves ischemia reperfusion-triggered acute kidney injury by activating Ambra1/ULK1-mediated autophagy

Ischemia reperfusion (I/R) was considered as one of main causes of acute kidney injury (AKI). However, the exact mechanism remains unclear. Here, this study aimed to investigate the role and mechanism of the m6A demethylase fat mass and obesity-associated (FTO) protein in I/R-induced AKI. HK-2 cells and SD rats were utilized to establish hypoxia/reoxygenation (H/R) or I/R induced AKI models. The changes of RNAs and proteins were quantified using RT-qPCR, western blot, and immunofluorescence assays, respectively. Cell proliferation and apoptosis were assessed by CCK-8 and flow cytometry. Interactions between molecules were investigated using RIP, ChIP, Co-IP, RNA pull-down, and dual luciferase reporter assays. Global m6A quantification was evaluated by kits. TUNEL and HE staining were employed for histopathological examinations. Oxidative stress-related indicators and renal function were determined using ELISA assays. The FTO expression was downregulated in H/R-induced HK-2 cells and renal tissues from I/R-induced rats. Overexpression of FTO improved the cell viability but repressed apoptosis and oxidative stress in H/R-treated HK-2 cells, as well as enhanced renal function and alleviated kidney injury in I/R rats. Notably, the FTO overexpression significantly increased autophagy-related LC3 and ULK1 levels. When autophagy was inhibited, the protective effects of FTO in AKI were diminished. Notably, Ambra1, a crucial regulator of autophagy, was repressed in H/R-induced HK-2 cells. However, the FTO overexpression restored the Ambra1 expression by reducing m6A modification of its mRNA. SP1, acting as an upstream transcription factor, directly interacts with the FTO promoter to enhance FTO expression. Knockdown of SP1 or Ambra1 suppressed the beneficial effects of FTO upregulation on autophagy and oxidative stress injury in H/R-stimulated cells. FTO, transcriptionally activated by SP1, promoted autophagy by upregulating Ambra1/ULK1 signaling, thereby inhibiting oxidative stress and kidney injury. These findings may provide some novel insights for AKI treatment.

Regulation of renal ischemia-reperfusion injury and tubular epithelial cell ferroptosis by pparγ m6a methylation: mechanisms and therapeutic implications

This study aimed to elucidate the role and underlying mechanisms of Peroxisome proliferator-activated receptor gamma (PPARγ) and its m6A methylation in renal ischemia-reperfusion (I/R) injury and ferroptosis of tubular epithelial cells (TECs). High-throughput transcriptome sequencing was performed on renal tissue samples from I/R injury models and sham-operated mice, complemented by in vivo and in vitro experiments focusing on the PPARγ activator Rosiglitazone and the manipulation of METTL14 and IGF2BP2 expression. Key evaluations included renal injury assessment, ferroptosis indicator measurement, and m6A methylation analysis of PPARγ. Our findings highlight the critical role of the PPARγ pathway and ferroptosis in renal I/R injury, with Rosiglitazone ameliorating renal damage and TEC ferroptosis. METTL14-mediated m6A methylation of PPARγ, dependent on IGF2BP2, emerged as a pivotal regulator of PPARγ expression, renal injury, and ferroptosis. This study reveals that PPARγ m6A methylation, orchestrated by METTL14 through an IGF2BP2-dependent mechanism, plays a crucial role in mitigating renal I/R injury and TEC ferroptosis. These insights offer promising avenues for therapeutic strategies targeting acute kidney injury.

Acyl-CoA Synthetase Long-Chain Isoenzymes in Kidney Diseases: Mechanistic Insights and Therapeutic Implications

Long-chain acyl-CoA synthetases (ACSLs) are pivotal enzymes in fatty acid metabolism, essential for maintaining cellular homeostasis and energy production. Recent research has uncovered their significant involvement in the pathophysiology of various kidney diseases, including acute kidney injury (AKI), chronic kidney disease (CKD), diabetic kidney disease (DKD), and renal cell carcinoma (RCC). While ACSL1, ACSL3, ACSL4, and ACSL5 have been extensively studied for their roles in processes such as ferroptosis, lipid peroxidation, renal fibrosis, epithelial-mesenchymal transition, and tumor progression, the role of ACSL6 in kidney diseases remain largely unexplored. Notably, these isoenzymes exhibit distinct functions in different kidney diseases. Therefore, to provide a comprehensive understanding of their involvement, this review highlights the molecular pathways influenced by ACSLs and their roles in modulating cell death, inflammation, and fibrosis during kidney disease progression. By examining these mechanisms in detail, this review underscores the potential of ACSLs as biomarkers and therapeutic targets, advocating for further research to elucidate the precise roles of individual ACSL isoenzymes in kidney disease progression. Understanding these mechanisms opens new avenues for developing targeted interventions and improving therapeutic outcomes for patients with kidney diseases.

The significance of ferroptosis in renal diseases and its therapeutic potential

Kidney diseases are significant global public health concern, with increasing prevalence and substantial economic impact. Developing novel therapeutic approaches are essential for delaying disease progression and improving patient quality of life. Cell death signifying the termination of cellular life, could facilitate appropriate bodily development and internal homeostasis. Recently, regulated cell death (RCD) forms such as ferroptosis, characterized by iron-dependent lipid peroxidation, has garnered attention in diverse renal diseases and other pathological conditions. This review offers a comprehensive examination of ferroptosis, encompassing an analysis of the involvement of iron and lipid metabolism, the System Xc - /glutathione/glutathione peroxidase 4 signaling, and additional associated pathways. Meanwhile, the review delves into the potential of targeting ferroptosis as a therapeutic approach in the management of acute kidney injury (AKI), chronic kidney disease (CKD), diabetic nephropathy, and renal tumors. Furthermore, it emphasizes the significance of ferroptosis in the transition from AKI to CKD and further accentuates the potential for repurposing drug and utilizing traditional medicine in targeting ferroptosis-related pathways for clinical applications. The integrated review provides valuable insights into the role of ferroptosis in kidney diseases and highlights the potential for targeting ferroptosis as a therapeutic strategy.

WTAP-mediated N6-methyladenosine modification promotes the inflammation, mitochondrial damage and ferroptosis of kidney tubular epithelial cells in acute kidney injury by regulating LMNB1 expression and activating NF-κB and JAK2/STAT3 pathways

Acute kidney injury (AKI) is a serious complication of sepsis patients, but the pathogenic mechanisms underlying AKI are still largely unclear. In this view, the roles of the key component of N6-methyladenosine (m6A)-wilms tumor 1 associated protein (WTAP) in AKI progression were investigated. AKI mice model was established by using cecal ligation and puncture (CLP). AKI cell model was established by treating HK-2 cells with LPS. Cell apoptosis was analyzed by TdT-mediated dUTP Nick-End Labeling (TUNEL) staining and flow cytometry analysis. Cell viability was analyzed by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay. The concentrations of inflammatory factors were examined with ELISA kits. Reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH) and Fe2+ levels were detected with related kits. Gene expression was detected by western blot assay or quantitative real-time polymerase chain reaction (qRT-PCR) assay. The relation between WTAP and lamin B1 (LMNB1) was verified by Methylated RNA Immunoprecipitation (meRIP) assay, RIP assay, dual-luciferase reporter assay and Actinomycin D assay. CLP induced significant pathological changes in kidney tissues in mice and promoted inflammation, mitochondrial damage and ferroptosis. LMNB1 level was induced in HK-2 cells by LPS. LMNB1 knockdown promoted LPS-mediated HK-2 cell viability and inhibited LPS-mediated HK-2 cell apoptosis, inflammation, mitochondrial damage and ferroptosis. Then, WTAP was demonstrated to promote LMNB1 expression by m6A Methylation modification. Moreover, WTAP knockdown repressed LPS-treated HK-2 cell apoptosis, inflammation, mitochondrial damage and ferroptosis, while LMNB1 overexpression reversed the effects. Additionally, WTAP affected the pathways of NF-κB and JAK2/STAT3 by LMNB1. WTAP-mediated m6A promoted the inflammation, mitochondrial damage and ferroptosis in LPS-induced HK-2 cells by regulating LMNB1 expression and activating NF-κB and JAK2/STAT3 pathways.

N6 methyladenosine eraser FTO suppresses Staphylococcus aureus-induced ferroptosis of bone marrow mesenchymal stem cells to ameliorate osteomyelitis through regulating the MDM2/TLR4/SLC7A11 signaling pathway

Osteomyelitis is a bone destructive inflammatory disease caused by infection. Ferroptosis is closely related to multiple inflammatory diseases, but the role of ferroptosis in Staphylococcus aureus (SA)-induced osteomyelitis remains unknown. In the present study, we found that SA treatment promoted the accumulation of iron, Fe2+ , lipid peroxide, and malondialdehyde, increased TFRC and reduced FTH1 and GPX4 to trigger ferroptosis in rat bone marrow mesenchymal stem cells (BMSCs). Interestingly, increased level of N6 methyl adenosine (m6A) modification along with decreased expression level of m6A eraser FTO were observed in SA-induced BMSCs, while upregulating FTO alleviated SA-triggered ferroptosis and protected cell viability in BMSCs. Mechanistically, MDM2 was identified as a target of FTO-mediated m6A demethylation, and FTO upregulation promoted MDM2 instability to downregulated TLR4 signal and elevate the expression of SLC7A11 and GPX4 in SA-induced BMSCs. Functional recovery experiments verified that overexpressing MDM2 or TLR4 reversed the inhibiting effect of FTO upregulation on ferroptosis in SA-treated BMSCs. Additionally, FTO upregulation restrained ferroptosis and pathological damage to bone tissue in SA-induced osteomyelitis model rats. Altogether, m6A eraser FTO alleviates SA-induced ferroptosis in osteomyelitis models partly through inhibiting the MDM2-TLR4 axis.

IGF2BP3-stabilized CAMK1 regulates the mitochondrial dynamics of renal tubule to alleviate diabetic nephropathy

BACKGROUND

CAMK1 has been shown to be involved in human disease progression via regulating mitochondrial dynamics. However, whether CAMK1 mediates mitochondrial dynamics to regulate diabetic nephropathy (DN) process remains unclear.

METHODS

Mice were injected with streptozotocin (STZ) to mimic diabetic mice models in vivo, and mice with proximal tubule-specific knockout of CAMK1 (CAMK1-KO) were generated. HK-2 cells were treated with high-glucose (HG) to mimic DN cell model in vitro. Histopathological analysis was performed to confirm kidney injury in mice. ROS production and apoptosis were assessed by DHE staining and TUNEL staining. Mitochondria morphology was observed and analyzed by electron microscopy. Mitochondrial membrane potential was detected by JC-1 staining, and cell proliferation was measured by EdU assay. The mRNA and protein expression were examined by qRT-PCR, western blot and immunostaining. RNA interaction was confirmed by RIP assay and dual-luciferase reporter assay. The mRNA stability was tested by actinomycin D treatment, and m6A level was examined by MeRIP assay.

RESULTS

CAMK1 was reduced in DN patients and STZ-induced diabetic mice. Conditional deletion of CAMK1 aggravated kidney injury and promoted mitochondrial fission in diabetic mice. CAMK1 overexpression inhibited mitochondrial fission to alleviate HG-induced HK-2 cell apoptosis. IGF2BP3 promoted the stability of CAMK1 mRNA by m6A modification. IGF2BP3 inhibited mitochondrial fission to repress cell apoptosis in vitro and kidney injury in vivo by increasing CAMK1 expression.

CONCLUSION

IGF2BP3-mediated CAMK1 mRNA stability alleviated DN progression by inhibiting mitochondria fission.

Role of epigenetically regulated inflammation in renal diseases

In recent decades, renal disease research has witnessed remarkable advances. Experimental evidence in this field has highlighted the role of inflammation in kidney disease. Epigenetic dynamics and immunometabolic reprogramming underlie the alterations in cellular responses to intrinsic and extrinsic stimuli; these factors determine cell identity and cell fate decisions and represent current research hotspots. This review focuses on recent findings and emerging concepts in epigenetics and inflammatory regulation and their effect on renal diseases. This review aims to summarize the role and mechanisms of different epigenetic modifications in renal inflammation and injury and provide new avenues for future research on inflammation-related renal disease and drug development.

SETD1A-mediated Methylation of H3K4me3 Inhibits Ferroptosis in Non-small Cell Lung Cancer by Regulating the WTAPP1/WTAP Axis

INTRODUCTION

SETD1A is upregulated in non-small cell lung cancer (NSCLC) tissues. This study investigated the molecular mechanism of the SETD1A/WTAPP1/WTAP axis in NSCLC.

METHODS

Ferroptosis is a unique cell death mode driven by iron-reliant phospholipid peroxidation, which is regulated by multiple cellular metabolic pathways, including REDOX homeostasis, iron metabolism, mitochondrial activity and metabolism of amino acids, lipids and sugars. Thus, the levels of ferroptosis markers (MDA, SOD, GSH) were measured in vitro, and NSCLC cell behaviors were assessed. SETD1A-mediated H3K4me3 methylation was analyzed. SETD1A-exerted effects on ferroptosis and tumor growth in vivo were verified in nude mouse models.

RESULTS

SETD1A was highly expressed in NSCLC cells. Silencing SETD1A suppressed NSCLC cell proliferation and migration, inhibited MDA, and enhanced GPX4, SOD, and GSH levels. SETD1A elevated WTAP expression through WTAPP1 upregulation by mediating H3K4me3 methylation in the WTAPP1 promoter region. WTAPP1 overexpression partly averted the promotional effect of silencing SETD1A on NSCLC cell ferroptosis. WTAP interference abrogated the inhibitory effects of WTAPP1 on NSCLC cell ferroptosis. Silencing SETD1A facilitated ferroptosis and accelerated tumor growth in nude mice through the WTAPP1/WTAP axis.

CONCLUSION

SETD1A amplified WTAP expression through WTAPP1 upregulation by mediating H3K4me3 modification in the WTAPP1 promoter region, thus promoting NSCLC cell proliferation and migration and inhibiting ferroptosis.

N6-methyladenosine (m6A) methylation in kidney diseases: Mechanisms and therapeutic potential

The N6-methyladenosine (m6A) modification is regulated by methylases, commonly referred to as "writers," and demethylases, known as "erasers," leading to a dynamic and reversible process. Changes in m6A levels have been implicated in a wide range of cellular processes, including nuclear RNA export, mRNA metabolism, protein translation, and RNA splicing, establishing a strong correlation with various diseases. Both physiologically and pathologically, m6A methylation plays a critical role in the initiation and progression of kidney disease. The methylation of m6A may also facilitate the early diagnosis and treatment of kidney diseases, according to accumulating research. This review aims to provide a comprehensive overview of the potential role and mechanism of m6A methylation in kidney diseases, as well as its potential application in the treatment of such diseases. There will be a thorough examination of m6A methylation mechanisms, paying particular attention to the interplay between m6A writers, m6A erasers, and m6A readers. Furthermore, this paper will elucidate the interplay between various kidney diseases and m6A methylation, summarize the expression patterns of m6A in pathological kidney tissues, and discuss the potential therapeutic benefits of targeting m6A in the context of kidney diseases.

METTL3-mediated N6-methyladenosine modification stimulates mitochondrial damage and ferroptosis of kidney tubular epithelial cells following acute kidney injury by modulating the stabilization of MDM2-p53-LMNB1 axis

N6-methyladenosine (m6A) and MELLT3 assume a role in the development of acute kidney injury (AKI). However, their mechanism in AKI remains under-explored. On this basis, this study explored the mechanism of MELLT3 in mitochondrial damage and ferroptosis of kidney tubular epithelial cells after AKI. HK-2 cells were induced by lipopolysaccharide (LPS) to simulate AKI, followed by gain and loss of function of genes, detection of mitochondrial damage and ferroptosis indicators, and analysis of gene interactions. An AKI mouse model was developed using the cecal ligation and puncture (CLP) method to investigate the effect of METTL3 knockdown on kidney injury. MDM2 and LMNB1 were upregulated and p53 was downregulated in LPS-treated HK-2 cells. Mechanistically, the E3 ubiquitin ligase MDM2 increased p53 ubiquitination to activate LMNB1. METTL3 knockdown decreased m6A methylation of MDM2, thus diminishing YTHDF1-mediated MDM2 mRNA stability and translation in LPS-treated HK-2 cells. Knockdown of LMNB1, MDM2, or METTL3 reduced NO, MDA, iron ion, and ROS levels as well as mitochondrial damage and raised SOD, GSH, XCT, GPX4, FPN1, and TFR1 levels in LPS-treated HK-2 cells. The in vivo results showed that METTL3 knockdown reduced renal injury and ferroptosis in CLP mice. METTL3 knockdown prevents mitochondrial damage and ferroptosis of kidney tubular epithelial cells after AKI via the MDM2-p53-LMNB1 axis.

N6-methyladenosine methylation in kidney injury

Multiple mechanisms are involved in kidney damage, among which the role of epigenetic modifications in the occurrence and development of kidney diseases is constantly being revealed. However, N6-methyladenosine (M6A), a well-known post-transcriptional modification, has been regarded as the most prevalent epigenetic modifications in higher eukaryotic, which is involved in various biological processes of cells such as maintaining the stability of mRNA. The role of M6A modification in the mechanism of kidney damage has attracted widespread attention. In this review, we mainly summarize the role of M6A modification in the progression of kidney diseases from the following aspects: the regulatory pattern of N6-methyladenosine, the critical roles of N6-methyladenosine in chronic kidney disease, acute kidney injury and renal cell carcinoma, and then reveal its potential significance in the diagnosis and treatment of various kidney diseases. A better understanding of this field will be helpful for future research and clinical treatment of kidney diseases.

Managing ferroptosis-related diseases with indirect dietary modulators of ferroptosis

Ferroptosis is an iron-dependent form of programmed cell death driven by excessive oxidation of polyunsaturated phospholipids on cellular membranes. Accumulating evidence suggests that ferroptosis has been implicated in the pathological process of various diseases, such as cardiovascular diseases, neurological diseases, liver diseases, kidney injury, lung injury, diabetes, and cancer. Targeting ferroptosis is therefore considered to be a reasonable strategy to fight against ferroptosis-associated diseases. Many dietary bioactive agents have been identified to be able to either suppress or promote ferroptosis, indicating that ferroptosis-based intervention by dietary approach may be an effective strategy for preventing and treating diseases associated with ferroptosis dysregulation. In this review, we summarize the present understanding of the functional role of ferroptosis in the pathogenesis of aforementioned diseases with an emphasis on the evidence of managing ferroptosis-related diseases with indirect dietary modulators of ferroptosis and propose issues that need to be addressed to promote practical application of dietary approach targeting ferroptosis.

Insights into the role of N6-methyladenosine in ferroptosis

N6-methyladenosine (m6A) methylation modification is one of the most prevalent epigenetic modifications of eukaryotic RNA. m6A methylation is widely associated with many biological processes through the modification of RNA metabolism and is associated with multiple disease states. As a newly discovered regulatory cell death in recent years, ferroptosis is an iron-dependent cell death characterized by excessive lipid peroxidation. Emerging evidence supports that ferroptosis has a significant role in the progression of diverse diseases. Besides, the key regulators of ferroptosis exhibit aberrant m6A levels under different pathological conditions. However, the correlation between m6A-modified ferroptosis and multiple diseases has not been well elucidated. In this review, we summarized the functions of m6A in ferroptosis, which are associated with the initiation and progression of multiple diseases. Investigating the role of m6A in ferroptosis might both facilitate a better understanding of the pathogenesis of these diseases and provide new opportunities for targeted treatment.

Identification of RPS7 as the Biomarker of Ferroptosis in Acute Kidney Injury

Objective

This paper aims to explore novel ferroptosis-related biomarkers for acute kidney injury (AKI).

Methods

Various bioinformatic methods, such as differential expression analysis, functional annotation analysis, machine learning, and chemical-gene network analysis, were used in this study. Furthermore, the expression and proferroptotic role of RPS7 were validated with further bioinformatics analysis and biochemical experiments.

Results

GSE30718 dataset and GSE139061 dataset were used, and the differentially expressed genes (DEGs) were screened. The DEGs were overlapped with ferroptosis-related genes and genes associated with AKI, which led to the identification of four candidate genes. Machine learning and ROC curve analysis were conducted, and RPS7 and TRIB3 were selected for diagnostic model analysis and functional analysis. Finally, the upregulation of RSP7 in cisplatin-induced AKI was validated in cisplatin-induced AKI, and its proferroptotic role was confirmed in cisplatin-treated proximal tubular cells.

Conclusion

Our results indicated that RPS7 might present as a novel ferroptosis-related biomarker for AKI, and it derived ferroptosis to accentuate cisplatin-induced AKI.