Circular RNA Arhgap12 modulates doxorubicin-induced cardiotoxicity by sponging miR-135a-5p

Adenylate cyclase 1 knockdown attenuates pirarubicin-induced cardiotoxicity

This study aimed to investigate the effects and possible mechanisms of adenylate cyclase 1 (ADCY1) on pirarubicin-induced cardiomyocyte injury. HL-1 cells were treated with pirarubicin (THP) to induce intracellular toxicity, and the extent of damage to mouse cardiomyocytes was assessed using CCK-8, Edu, flow cytometry, ROS, ELISA, RT-qPCR and western blotting. THP treatment reduced the viability of HL-1 cells, inhibited proliferation, induced apoptosis and triggered oxidative stress. In addition, the RT-qPCR results revealed that ADCY1 expression was significantly elevated in HL-1 cells, and molecular docking showed a direct interaction between ADCY1 and THP. Western blotting showed that ADCY1, phospho-protein kinase A and GRIN2D expression were also significantly elevated. Knockdown of ADCY1 attenuated THP-induced cardiotoxicity, possibly by regulating the ADCY1/PKA/GRIN2D pathway.

Research progress of circular RNAs in myocardial ischemia

Circular RNAs (circRNAs) are a type of single-stranded RNA that forms a covalently closed continuous loop. Its structure, stability, properties, and cell- and tissue-specificity have gained considerable recognition in the research and clinical sectors, as its role has been observed in different diseases, such as cardiovascular diseases, cancers, and central nervous system diseases, etc. Cardiovascular disease is still named as the number one cause of death globally, with myocardial ischemia (MI) accounting for 15 % of mortality annually. A number of circRNAs have been identified and are being studied for their ability to reduce MI by inhibiting the molecular mechanisms associated with myocardial ischemia reperfusion injury, such as inflammation, oxidative stress, autophagy, apoptosis, and so on. CircRNAs play a significant role as crucial regulatory elements at transcriptional levels, regulating different proteins, and at posttranscriptional levels, having interactions with RNA-binding proteins, ribosomal proteins, micro-RNAS, and long non-coding RNAS, making it possible to exert their effects through the circRNA-miRNA-mRNA axis. CircRNAs are a potential novel biomarker and therapeutic target for myocardial ischemia and cardiovascular diseases in general. The purpose of this review is to summarize the relationship, function, and mechanism observed between circRNAs and MI injury, as well as to provide directions for future research and clinical trials.

The Role of Circular RNA in the Pathogenesis of Chemotherapy-Induced Cardiotoxicity in Cancer Patients: Focus on the Pathogenesis and Future Perspective

Cardiotoxicity is a serious challenge cancer patients face today. Various factors are involved in cardiotoxicity. Circular RNAs (circRNAs) are one of the effective factors in the occurrence and prevention of cardiotoxicity. circRNAs can lead to increased proliferation, apoptosis, and regeneration of cardiomyocytes by regulating the molecular pathways, as well as increasing or decreasing gene expression; some circRNAs have a dual role in cardiomyocyte regeneration or death. Identifying each of the pathways related to these processes can be effective on managing patients and preventing cardiotoxicity. In this study, an overview of the molecular pathways involved in cardiotoxicity by circRNAs and their effects on the downstream factors have been discussed.

Precision Treatment of Anthracycline-Induced Cardiotoxicity: An Updated Review

OPINION STATEMENT

Anthracycline (ANT)-induced cardiotoxicity (AIC) is a particularly prominent form of cancer therapy-related cardiovascular toxicity leading to the limitations of ANTs in clinical practice. Even though AIC has drawn particular attention, the best way to treat it is remaining unclear. Updates to AIC therapy have been made possible by recent developments in research on the underlying processes of AIC. We review the current molecular pathways leading to AIC: 1) oxidative stress (OS) including enzymatic-induced and other mechanisms; 2) topoisomerase; 3) inflammatory response; 4) cardiac progenitor cell damage; 5) epigenetic changes; 6) renin-angiotensin-aldosterone system (RAAS) dysregulation. And we systematically discuss current prevention and treatment strategies and novel pathogenesis-based therapies for AIC: 1) dose reduction and change; 2) altering drug delivery methods; 3) antioxidants, dexrezosen, statina, RAAS inhibitors, and hypoglycemic drugs; 4) miRNA, natural phytochemicals, mesenchymal stem cells, and cardiac progenitor cells. We also offer a fresh perspective on the management of AIC by outlining the current dilemmas and challenges associated with its prevention and treatment.

The role and mechanism of epigenetics in anticancer drug-induced cardiotoxicity

Cardiovascular disease is the main factor contributing to the global burden of diseases, and the cardiotoxicity caused by anticancer drugs is an essential component that cannot be ignored. With the development of anticancer drugs, the survival period of cancer patients is prolonged; however, the cardiotoxicity caused by anticancer drugs is becoming increasingly prominent. Currently, cardiovascular disease has emerged as the second leading cause of mortality among long-term cancer survivors. Anticancer drug-induced cardiotoxicity has become a frontier and hot topic. The discovery of epigenetics has given the possibility of environmental changes in gene expression, protein synthesis, and traits. It has been found that epigenetics plays a pivotal role in promoting cardiovascular diseases, such as heart failure, coronary heart disease, and hypertension. In recent years, increasing studies have underscored the crucial roles played by epigenetics in anticancer drug-induced cardiotoxicity. Here, we provide a comprehensive overview of the role and mechanisms of epigenetics in anticancer drug-induced cardiotoxicity.

CircHDAC9 regulates myocardial ischemia-reperfusion injury via miR-671-5p/SOX4 signaling axis

BACKGROUND

Myocardial ischemia-reperfusion (I/R), a harmful process in the treatment of cardiovascular diseases, can cause secondary damage to the cardiac tissues. Circular RNAs (circRNAs) are important regulators in a number of cardiac disorders. However, the role of circHDAC9 in myocardial I/R injury has not been clarified.

METHODS

Human cardiac myocytes (HCMs) were treated with hypoxia/reoxygenation (H/R) and mice were subjected to I/R. Quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) was used to analyze the expression of circHDAC9, miR-671-5p, and SOX4, and western blot was used to detect SOX4 protein. The binding relationship among circHDAC9, miR-671-5p, and SOX4 was confirmed by RNA pull-down, luciferase, and RNA immunoprecipitation (RIP) assays. The effects of circHDAC9/miR-671-5p/SOX4 axis on the apoptosis, oxidative stress and inflammation were evaluated in both myocardial I/R injury models.

RESULTS

The expression of circHDAC9 and SOX4 was noticeably elevated, whereas miR-671-5p expression was downregulated in both myocardial I/R injury models. circHDAC9 knockdown significantly reduced the apoptosis, activities of caspase-3 and caspase-9, ROS intensity, MDA activity, and concentrations of TNF-α, IL-1β, and IL-6, but increased the viability and SOD activity in H/R-treated HCMs. Suppression of circHDAC9 dramatically reduced the levels of circHDAC9 and SOX4, while enhanced miR-671-5p expression in H/R-treated HCMs. CircHDAC9 functioned via sponging miR-671-5p to regulate SOX4 expression in vitro. Additionally, silencing of circHDAC9 improved the pathological abnormalities and cardiac dysfunction, and reduced the apoptosis, oxidative stress and inflammation in mice with myocardial I/R injury.

CONCLUSIONS

Inhibition of circHDAC9 significantly improved myocardial I/R injury by regulating miR-671-5p/SOX4 signaling pathway.

Exploring the Multifaceted Biologically Relevant Roles of circRNAs: From Regulation, Translation to Biomarkers

CircRNAs are a category of regulatory RNAs that have garnered significant attention in the field of regulatory RNA research due to their structural stability and tissue-specific expression. Their circular configuration, formed via back-splicing, results in a covalently closed structure that exhibits greater resistance to exonucleases compared to linear RNAs. The distinctive regulation of circRNAs is closely associated with several physiological processes, as well as the advancement of pathophysiological processes in several human diseases. Despite a good understanding of the biogenesis of circular RNA, details of their biological roles are still being explored. With the steady rise in the number of investigations being carried out regarding the involvement of circRNAs in various regulatory pathways, understanding the biological and clinical relevance of circRNA-mediated regulation has become challenging. Given the vast landscape of circRNA research in the development of the heart and vasculature, we evaluated cardiovascular system research as a model to critically review the state-of-the-art understanding of the biologically relevant functions of circRNAs. We conclude the review with a discussion of the limitations of current functional studies and provide potential solutions by which these limitations can be addressed to identify and validate the meaningful and impactful functions of circRNAs in different physiological processes and diseases.

A CircRNA-miRNA-mRNA Network for Exploring Doxorubicin- and Myocet-Induced Cardiotoxicity in a Translational Porcine Model

Despite the widespread use of doxorubicin (DOX) as a chemotherapeutic agent, its severe cumulative cardiotoxicity represents a significant limitation. While the liposomal encapsulation of doxorubicin (Myocet, MYO) reduces cardiotoxicity, it is crucial to understand the molecular background of doxorubicin-induced cardiotoxicity. Here, we examined circular RNA expression in a translational model of pigs treated with either DOX or MYO and its potential impact on the global gene expression pattern in the myocardium. This study furthers our knowledge about the regulatory network of circRNA/miRNA/mRNA and its interaction with chemotherapeutics. Domestic pigs were treated with three cycles of anthracycline drugs (DOX, n = 5; MYO, n = 5) to induce cardiotoxicity. Untreated animals served as controls (control, n = 3). We applied a bulk mRNA-seq approach and the CIRIquant algorithm to identify circRNAs. The most differentially regulated circRNAs were validated under cell culture conditions, following forecasting of the circRNA-miRNA-mRNA network. We identified eight novel significantly regulated circRNAs from exonic and mitochondrial regions in the porcine myocardium. The forecasted circRNA-miRNA-mRNA network suggested candidate circRNAs that sponge miR-17, miR-15b, miR-130b, the let-7 family, and miR125, together with their mRNA targets. The identified circRNA-miRNA-mRNA network provides an updated, coherent view of the mechanisms involved in anthracycline-induced cardiotoxicity.

Circ_0001667 Promotes Adriamycin Resistance and Malignant Progression via Targeting the miR-193a-5p/Rap2A Molecular Axis in Breast Cancer

BACKGROUND

The therapeutic effect of adriamycin (ADM) has been limited by chemoresistance in breast cancer (BC). Circular RNAs are involved in resistance regulation by mediating the miRNA/mRNA axis. Circ_0001667 enhanced ADM resistance via the miR-4458/NCOA3 axis in BC. This study was to investigate the other miRNA/mRNA network for circ_0001667.

METHODS

The level detection of circ_0001667, microRNA-193a-5p (miR-193a-5p) or Ras-Related Protein 2a (Rap2A) was conducted by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Half inhibitory concentration (IC₅₀) of ADM was detected through cell counting kit-8 (CCK-8) assay. The proliferation analysis was performed by colony formation assay and EdU assay. Flow cytometry was used for assessing apoptosis. Transwell assay was applied for examining cell migration and invasion. The protein detection was carried out by western blot. In vivo assay was performed using xenograft tumor model. Dual-luciferase reporter and RNA immunoprecipitation (RIP) assays were implemented to validate the target interaction.

RESULTS

Circ_0001667 was highly expressed in ADM-resistant BC tissues and cells. Downregulation of circ_0001667 reduced ADM resistance and inhibited proliferation, migration, invasion in ADM-resistant BC cells. Tumor growth was repressed by circ_0001667 knockdown in ADM-resistant xenograft model. Circ_0001667 has induced the sponge effect on miR-193a-5p. The circ_0001667 function was partly achieved by targeting miR-193a-5p. Rap2A expression was positively regulated by circ_0001667 through sponging miR-193a-5p. The miR-193a-5p upregulation restrained chemoresistance and BC progression by the downregulation of Rap2A.

CONCLUSION

All results unraveled that circ_0001667 contributed to ADM resistance and tumor development in BC via the miR-193a-5p-mediated Rap2A expression change, providing a novel regulatory mechanism for circ_0001667.

Emerging roles of circular RNAs in cancer therapy-induced cardiotoxicity

Cancer therapy-induced cardiotoxicity (CTIC) is an important cause of death in cancer survivors which often results in the withdrawal or discontinuation of drugs. The underlying mechanisms of CTIC remain unclear. Circular RNAs (circRNAs) are a class of non-coding regulatory RNA molecules which have emerged in recent years. They are generated by back splicing and have powerful biological functions, including transcription and splicing, isolating or building macromolecular scaffolds to interfere with microRNA activity and signaling pathways, and acting as templates for translation. Moreover, circRNAs demonstrate high abundance and significant stability. CircRNAs can be used as novel biomarkers because they often function in a cell-type and tissue-specific manner. CircRNAs have attracted increasing attention in cardiovascular disease research, and recent studies exploring the role of circRNAs in CTIC have had promising results. This review will summarize the current understanding of circRNAs' biogenesis, regulation and function. Their clinical potential as biomarkers, therapeutic agents and drug targets will also be explored.

Epigenetic regulation in myocardial infarction: Non-coding RNAs and exosomal non-coding RNAs

Myocardial infarction (MI) is one of the leading causes of deaths globally. The early diagnosis of MI lowers the rate of subsequent complications and maximizes the benefits of cardiovascular interventions. Many efforts have been made to explore new therapeutic targets for MI, and the therapeutic potential of non-coding RNAs (ncRNAs) is one good example. NcRNAs are a group of RNAs with many different subgroups, but they are not translated into proteins. MicroRNAs (miRNAs) are the most studied type of ncRNAs, and have been found to regulate several pathological processes in MI, including cardiomyocyte inflammation, apoptosis, angiogenesis, and fibrosis. These processes can also be modulated by circular RNAs and long ncRNAs via different mechanisms. However, the regulatory role of ncRNAs and their underlying mechanisms in MI are underexplored. Exosomes play a crucial role in communication between cells, and can affect both homeostasis and disease conditions. Exosomal ncRNAs have been shown to affect many biological functions. Tissue-specific changes in exosomal ncRNAs contribute to aging, tissue dysfunction, and human diseases. Here we provide a comprehensive review of recent findings on epigenetic changes in cardiovascular diseases as well as the role of ncRNAs and exosomal ncRNAs in MI, focusing on their function, diagnostic and prognostic significance.

Non-coding RNAs in cancer therapy-induced cardiotoxicity: Mechanisms, biomarkers, and treatments

As a result of ongoing breakthroughs in cancer therapy, cancer patients' survival rates have grown considerably. However, cardiotoxicity has emerged as the most dangerous toxic side effect of cancer treatment, negatively impacting cancer patients' prognosis. In recent years, the link between non-coding RNAs (ncRNAs) and cancer therapy-induced cardiotoxicity has received much attention and investigation. NcRNAs are non-protein-coding RNAs that impact gene expression post-transcriptionally. They include microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). In several cancer treatments, such as chemotherapy, radiotherapy, and targeted therapy-induced cardiotoxicity, ncRNAs play a significant role in the onset and progression of cardiotoxicity. This review focuses on the mechanisms of ncRNAs in cancer therapy-induced cardiotoxicity, including apoptosis, mitochondrial damage, oxidative stress, DNA damage, inflammation, autophagy, aging, calcium homeostasis, vascular homeostasis, and fibrosis. In addition, this review explores potential ncRNAs-based biomarkers and therapeutic strategies, which may help to convert ncRNAs research into clinical practice in the future for early detection and improvement of cancer therapy-induced cardiotoxicity.

MiRNAs and circRNAs for the Diagnosis of Anthracycline-Induced Cardiotoxicity in Breast Cancer Patients: A Narrative Review

Breast cancer (BC) is the most frequent type of female cancer with increasing incidence in recent years. Doxorubicin (DOX) is an important backbone chemotherapy in BC, responsible for cardiotoxicity (CTX) in about 9% of treated women within the first year. Biomarkers of early CTX diagnosis are essential to avoid complicated DOX-related cardiac diseases. Traditional serum biomarkers are either poorly sensitive with transient elevation, and even absent if investigated outside their diagnostic window, or arise only in late-stage CTX. Emerging biomarkers such as non-coding RNA (ncRNA) have been recently investigated in DOX-related CTX. In our review, we revised the role of microRNAs, the most studied type of ncRNA, both in animal and human models, highlighting the interesting but often contrasting results. Moreover, we reviewed a novel class of ncRNA, circular RNA (circRNA), focusing on their modulatory mechanisms also involving microRNAs. MicroRNA and circRNA are players in a wide homeostatic balance with their perturbation representing a possible compensation for DOX damage. Further studies are required to assess the modalities of early detection of their variation in BC patients suffering from heart disease induced by DOX treatment.

Noncoding RNA-Associated Competing Endogenous RNA Networks in Doxorubicin-Induced Cardiotoxicity

Accumulating evidence has indicated that noncoding RNAs (ncRNAs) are involved in doxorubicin-induced cardiotoxicity (DIC). However, the ncRNA-associated competing endogenous RNA (ceRNA)-mediated regulatory mechanisms in DIC remain unclear. In this study, we aimed to systematically investigate the alterations in expression levels of long noncoding RNA (lncRNA), circular RNA (circRNA), microRNA (miRNA), and mRNA in a DIC mouse model through deep RNA sequencing (RNA-seq). The results showed that 217 lncRNAs, 41 circRNAs, 11 miRNAs and 3633 mRNAs were aberrantly expressed. Moreover, the expression of 12 randomly selected transcripts was determined by real-time quantitative polymerase chain reaction to test the reliability of RNA-seq data. Based on the interaction between miRNAs and mRNAs, as well as lncRNAs/circRNAs and miRNAs, we constructed comprehensive lncRNA or circRNA-associated ceRNA networks in DIC mice. Moreover, we performed Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses for differentially expressed genes. In conclusion, these identified ceRNA interactions provide new insight into the underlying mechanism and may be crucial therapeutic targets of DIC.

microRNA-135a-5p regulates NOD-like receptor family pyrin domain containing 3 inflammasome-mediated hypertensive cardiac inflammation and fibrosis via thioredoxin-interacting protein

Hypertension is a severe public health problem that induces cardiac injury with alterations of gene expressions. The current study sought to evaluate the mechanism of microRNA(miR)-135a-5p in NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome-mediation of cardiac inflammation and hypertensive cardiac fibrosis. Firstly, hypertensive mouse models were established using angiotensin II (Ang II), followed by miR-135a-5p agomir treatment. Subsequently, mouse blood pressure and basic cardiac function indexes, histopathological changes, and cardiac fibrosis were all determined, in addition to detection of factors related to inflammation and fibrosis. Additionally, mice cardiac fibroblasts (CFs) were isolated and treated with Ang II. The binding relationship of miR-135a-5p and thioredoxin-interacting protein (TXNIP) was predicted and testified, while the interaction of TXNIP and NLRP3 was detected by means of a co-immunoprecipitation assay. It was found that miR-135a-5p was poorly-expressed in Ang II-treated mice and further exerted cardioprotective effects against hypertensive heart diseases. Moreover, over-expression of miR-135a-5p resulted in inhibition of inflammatory infiltration and almost eliminated cardiac fibrosis, as evidenced by decreased Collagen (COL)-I, COL-III, a-smooth muscle actin, NLRP3, tumor necrosis factor-α, and interleukin-6. Mechanically, miR-135a-5p inhibited TXNIP expression to block the binding of TXNIP and NLRP3. On the other hand, TXNIP up-regulation reversed the protective role of miR-135a-5p over-expression in CFs. Collectively, our findings indicated that miR-135a-5p over-expression inhibited TXNIP expression to block the binding of TXNIP and NLRP3, thereby alleviating hypertensive cardiac inflammation and fibrosis.

Circ-LTBP1 is involved in doxorubicin-induced intracellular toxicity in cardiomyocytes via miR-107/ADCY1 signal

Although doxorubicin (DOX) is a broad-spectrum and anthracycline chemotherapeutic agent, cardiotoxicity limits its clinical application. Therefore, it is meant to prevent the clinical side effects of DOX. Human cardiomyocyte-like AC16 cells were treated with DOX to induce intracellular toxicity. AC16 cell viability was determined by Cell Counting Kit 8 and 5-ethynyl-2'-deoxyuridine assays. The tumor necrosis factor-α and interleukin-6 abundances were quantified by matched kits. The apoptosis rate was measured by flow cytometry. Western blot analysis was conducted to measure the protein expression levels in AC16 cells. Oxidative stress was analyzed by measuring superoxide dismutase and malondialdehyde production. The quantitative real-time polymerase chain reaction was conducted to assess the expression levels of circ-latent transforming growth factor-beta binding protein-1 (circ-LTBP1), microRNA-107 (miR-107), and Adenylate cyclase 1 (ADCY1) expression in AC16 cells. The interaction relationship among circ-LTBP1, miR-107, and ADCY1 was verified by dual-luciferase reporter and RNA immunoprecipitation assays. As a result, treatment with DOX induced the proliferation inhibition, inflammation, apoptosis, and oxidative stress in AC16 cells, which were rescued by circ-LTBP1 inhibition or miR-107 upregulation. MiR-107 was confirmed as a target of circ-LTBP1, and inhibition of circ-LTBP1-mediated effects on DOX-stimulated cells were abolished by downregulation of miR-107. Circ-LTBP1 mediated ADCY1 expression by sponging miR-107 in AC16 cells. The upregulation of miR-107 increased cell proliferation and inhibited inflammation, apoptosis, and oxidative stress in DOX-stimulated cells through downregulation of ADCY1. Circ-LTBP1 was found to enhance DOX-induced effects on proliferation inhibition, inflammation, apoptosis, and oxidative stress in AC16 cells through competitively sponging miR-107 and elevating ADCY1.

Underlying the Mechanisms of Doxorubicin-Induced Acute Cardiotoxicity: Oxidative Stress and Cell Death

Cancer is a destructive disease that causes high levels of morbidity and mortality. Doxorubicin (DOX) is a highly efficient antineoplastic chemotherapeutic drug, but its use places survivors at risk for cardiotoxicity. Many studies have demonstrated that multiple factors are involved in DOX-induced acute cardiotoxicity. Among them, oxidative stress and cell death predominate. In this review, we provide a comprehensive overview of the mechanisms underlying the source and effect of free radicals and dependent cell death pathways induced by DOX. Hence, we attempt to explain the cellular mechanisms of oxidative stress and cell death that elicit acute cardiotoxicity and provide new insights for researchers to discover potential therapeutic strategies to prevent or reverse doxorubicin-induced cardiotoxicity.

Research Progress of circRNAs in Inflammatory Mechanisms of Diabetic Retinopathy: An Emerging Star with Potential Therapeutic Targets

PURPOSE

 We summarized the existing studies to elaborate the biogenesis and function of circRNAs, the effect of aberrant circRNAs expression in the mechanism of inflammation and diabetic retinopathy (DR) respectively and further explored the vital roles of circRNAs in inflammation involved in DR. Methods: We conducted a systematical literature search of abundant electronic databases (PubMed, GeneMedical and MEDLINE) up to August 2021. Results: In this review, we exhibited the biogenesis and function of circRNAs and highlighted the components of inflammatory mediators implicated in DR. Numerous circRNAs, such as circHIPK3, circZNF609, circRNA_0084043, circ_0002570, circ_0041795, circEhmt1 and circ-ITCH were discovered to play vital roles in inflammation involved in DR, which provided new ideas for diagnosis and treatment of DR. Moreover, we proposed not only the epigenetic functions of circRNAs but also novel forms of the inflammatory response, including pyroptosis, to inspire further exploration and creative research in this field. Conclusion: CircRNAs were implicated in the progression and development of inflammation in DR via aberrant expression and modulation of gene expression, serving as an emerging star with potential therapeutic targets.

Emerging roles of circRNAs in the pathological process of myocardial infarction

Myocardial infarction (MI) is defined as cardiomyocyte death in a clinical context consistent with ischemic insult. MI remains one of the leading causes of morbidity and mortality worldwide. Although there are a number of effective clinical methods for the diagnosis and treatment of MI, further investigation of novel biomarkers and molecular therapeutic targets is required. Circular RNAs (circRNAs), novel non-coding RNAs, have been reported to function mainly by acting as microRNA (miRNA) sponges or binding to RNA-binding proteins (RBPs). The circRNA-miRNA-mRNA (protein) regulatory pathway regulates gene expression and affects the pathological mechanisms of various diseases. Undoubtedly, a more comprehensive understanding of the relationship between MI and circRNA will lay the foundation for the development of circRNA-based diagnostic and therapeutic strategies for MI. Therefore, this review summarizes the pathophysiological process of MI and various approaches to measure circRNA levels in MI patients, tissues, and cells; highlights the significance of circRNAs in the regulation MI pathogenesis and development; and provides potential clinical insight for the diagnosis, prognosis, and treatment of MI.

Integrating analysis of circular RNA and mRNA expression profiles in doxorubicin induced cardiotoxicity mice

Doxorubicin (DOX)-induced cardiotoxicity impedes its clinical application, but the mechanisms have not been thoroughly elucidated. Based on circRNA and mRNA expression profiles, we illustrated RNA expression signature changes during DOX-induced cardiotoxicity; mechanism exploration and biomarkers screening were also conducted. Twelve mice were randomly divided into two groups, induction group was treated with doxorubicin, and the control group was given an equal quantity of saline. After the confirmation of myocardial injury in induction group, the heart tissues from both groups were isolated for RNA high-throughput sequencing. The expression profiles were compared between the two groups; a total of 295 mRNAs and 11 circRNAs were shown as biased expression in DOX-induced cardiotoxicity mouse hearts. The dysregulation of three circRNAs were validated by quantitative real-time PCR: mmu_circ_0015773, mmu_circ_0002106, and mmu_circ_001606. In addition, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses of the differentially expressed RNAs were performed; the results implied that DOX might cause cardiotoxicity by interfering hemoglobin-based oxygen delivery and DNA-associated signal pathways. We integrated the differential expressed mRNA and validated circRNAs by constructing a competing endogenous RNA (ceRNA) network, which indicated that the alteration of the three circRNAs could activate apoptosis process of myocardial cells. This study provided novel insight into the mechanisms of DOX induced cardiotoxicity, and potential biomarkers or therapeutic targets were also proposed.

Mechanism of total glucosides of paeony in hypoxia/reoxygenation-induced cardiomyocyte pyroptosis

Inflammasome-mediated pyroptosis can aggravate myocardial ischemia/reperfusion injury. Total glucosides of paeony (TGP) is widely used in anti-inflammation. This study investigated the effect of TGP on pyroptosis of hypoxia/reoxygenation (H/R)-induced cardiomyocytes. HL-1 cells were subjected to H/R treatment. H/R-induced cardiomyocytes were treated with TGP at different concentrations (50, 100, and 200 mg/kg). The viability of H/R-induced cardiomyocytes was measured. The levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD), and reactive oxygen species (ROS) were determined. The activity of caspase-1, the expressions of NLRP3 and GSDMD-N, and the concentrations of IL-1β and IL-18 were examined. miR-181a-5p expression in H/R cardiomyocytes was determined. The targeting relationship between miR-181a-5p and adenylate cyclase 1 (ADCY1) was verified. Functional rescue experiments were performed to verify the effect of miR-181a-5p or ADCY1 on the pyroptosis of H/R cardiomyocytes. TGP enhanced H/R-induced cardiomyocyte viability in a dose-dependent manner, reduced LDH, MDA, and ROS levels, increased SOD level, decreased caspase-1 activity, reduced NLRP3 and GSDMD-N expressions, and inhibited IL-1β and IL-18 concentrations. TGP suppressed miR-181a-5p expression in H/R cardiomyocytes. miR-181a-5p targeted ADCY1. miR-181a-5p overexpression or ADCY1 inhibition reversed the inhibitory effect of TGP on the pyroptosis of H/R cardiomyocytes. Collectively, TGP alleviated the pyroptosis of H/R cardiomyocytes via the miR-181a-5p/ADCY1 axis.

IGF2BP2-modified circular RNA circARHGAP12 promotes cervical cancer progression by interacting m6A/FOXM1 manner

Emerging evidence indicates that circular RNA (circRNA) and N⁶-methyladenosine (m⁶A) play critical roles in cervical cancer. However, the synergistic effect of circRNA and m⁶A on cervical cancer progression is unclear. In the present study, our sequencing data revealed that a novel m⁶A-modified circRNA (circARHGAP12, hsa_circ_0000231) upregulated in the cervical cancer tissue and cells. Interestingly, the m⁶A modification of circARHGAP12 could amplify its enrichment. Functional experiments illustrated that circARHGAP12 promoted the tumor progression of cervical cancer in vivo and vitro. Furthermore, MeRIP-Seq illustrated that there was a remarkable m⁶A site in FOXM1 mRNA. CircARHGAP12 interacted with m⁶A reader IGF2BP2 to combine with FOXM1 mRNA, thereby accelerating the stability of FOXM1 mRNA. In conclusion, we found that circARHGAP12 exerted the oncogenic role in cervical cancer progression through m⁶A-dependent IGF2BP2/FOXM1 pathway. These findings may provide new concepts for cervical cancer biology and pathological physiology.

Circular RNA: A novel type of biomarker for glioma (Review)

With the rapid development of sequencing technologies, the characteristics and functions of circular RNAs (circRNAs) in different tissues, and their underlying pathophysiological mechanisms, have been identified. circRNAs are significantly enriched in the brain and are continually expressed from the embryonic stage to the adult stage in rats. Previous studies have reported that certain circRNAs are differentially expressed in glioma and regulate a number of biological processes, such as cell proliferation, metastasis and oncogenesis of glioma. Furthermore, certain circRNAs have been associated with tumor size, World Health Organization tumor grade and poor prognosis in patients with glioma. It has been hypothesized that circRNAs may be involved in the onset and progression of glioma through transcriptional regulation, protein translation and binding to microRNAs. These properties and functions suggest the potential of circRNAs as prognostic biomarkers and therapeutic targets for glioma. For the present review, published studies were examined from PubMed, Embase, Cochrane Central and the reference lists of the retrieved articles. The aim of the present review was to summarize the progress of circRNA research in glioma, discuss the potential diagnostic and prognostic values, and the roles of circRNAs in glioma, and provide a novel theoretical basis and research concepts for the prediction, diagnosis and treatment of glioma.