LncRNA KCNQ1OT1 contributes to cardiomyocyte apoptosis by targeting FUS in heart failure

Circulating Non-Coding RNAs as Indicators of Fibrosis and Heart Failure Severity

Heart failure (HF) is a leading cause of morbidity and mortality worldwide, representing a complex clinical syndrome in which the heart's ability to pump blood efficiently is impaired. HF can be subclassified into heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF), each with distinct pathophysiological mechanisms and varying levels of severity. The progression of HF is significantly driven by cardiac fibrosis, a pathological process in which the extracellular matrix undergoes abnormal and uncontrolled remodelling. Cardiac fibrosis is characterized by excessive matrix protein deposition and the activation of myofibroblasts, increasing the stiffness of the heart, thus disrupting its normal structure and function and promoting lethal arrythmia. MicroRNAs, long non-coding RNAs, and circular RNAs, collectively known as non-coding RNAs (ncRNAs), have recently gained significant attention due to a growing body of evidence suggesting their involvement in cardiac remodelling such as fibrosis. ncRNAs can be found in the peripheral blood, indicating their potential as biomarkers for assessing HF severity. In this review, we critically examine recent advancements and findings related to the use of ncRNAs as biomarkers of HF and discuss their implication in fibrosis development.

The Biological Mechanisms and Clinical Roles of RNA-Binding Proteins in Cardiovascular Diseases

RNA-binding proteins (RBPs) have pivotal roles in cardiovascular biology, influencing various molecular mechanisms underlying cardiovascular diseases (CVDs). This review explores the significant roles of RBPs, focusing on their regulation of RNA alternative splicing, polyadenylation, and RNA editing, and their impact on CVD pathogenesis. For instance, RBPs are crucial in myocardial injury, contributing to disease progression and repair mechanisms. This review systematically analyzes the roles of RBPs in myocardial injury, arrhythmias, myocardial infarction, and heart failure, revealing intricate interactions that influence disease outcomes. Furthermore, the potential of RBPs as therapeutic targets for cardiovascular dysfunction is explored, highlighting the advances in drug development and clinical research. This review also discusses the emerging role of RBPs as biomarkers for cardiovascular diseases, offering insights into their diagnostic and prognostic potential. Despite significant progress, current research faces several limitations, which are critically examined. Finally, this review identifies the major challenges and outlines future research directions to advance the understanding and application of RBPs in cardiovascular medicine.

Protective Effect of Long Noncoding RNA OXCT1-AS1 on Doxorubicin-Induced Apoptosis of Human Myocardial Cells by the Competitive Endogenous RNA Pattern

BACKGROUND

The anthracycline chemotherapeutic antibiotic doxorubicin (DOX) can induce cumulative cardiotoxicity and lead to cardiac dysfunction. Long non-coding RNAs (lncRNAs) can function as important regulators in DOX-induced myocardial injury.

OBJECTIVE

This study aims to investigate the functional role and molecular mechanism of lncRNA OXCT1 antisense RNA 1 (OXCT1-AS1) in DOX-induced myocardial cell injury in vitro.

METHODS

Human cardiomyocytes (AC16) were stimulated with DOX to induce a myocardial cell injury model. OXCT1-AS1, miR-874-3p, and BDH1 expression in AC16 cells were determined by RT-qPCR. AC16 cell viability was measured by XTT assay. Flow cytometry was employed to assess the apoptosis of AC16 cells. Western blotting was used to evaluate protein levels of apoptosis-related markers. Dual-luciferase reporter assay was conducted to verify the binding ability between miR-874-3p and OXCT1-AS1 and between miR-874-3p and BDH1. The value of p<0.05 indicated statistical significance.

RESULTS

OXCT1-AS1 expression was decreased in DOX-treated AC16 cells. Overexpression of OXCT1-AS1 reversed the reduction of cell viability and promotion of cell apoptosis caused by DOX. OXCT1-AS1 is competitively bound to miR-874-3p to upregulate BDH1. BDH1 overexpression restored AC16 cell viability and suppressed cell apoptosis under DOX stimulation. Knocking down BDH1 reversed OXCT1-AS1-mediated attenuation of AC16 cell apoptosis under DOX treatment.

CONCLUSION

LncRNA OXCT1-AS1 protects human myocardial cells AC16 from DOX-induced apoptosis via the miR-874-3p/BDH1 axis.

Arginine vasopressin induces ferroptosis to promote heart failure via activation of the V1aR/CaN/NFATC3 pathway

Arginine vasopressin (AVP) is a key contributor to heart failure (HF), but the underlying mechanisms remain unclear. In the present study, a mouse model of HF and human cardiomyocyte (HCM) cells treated with dDAVP are generated in vivo and in vitro, respectively. Hematoxylin and eosin (HE) staining is used to evaluate the morphological changes in the myocardial tissues. A colorimetric method is used to measure the iron concentration, Fe 2+ concentration and malondialdehyde (MDA) level. Western blot analysis is used to examine the protein levels of the V1a receptor (V1aR), calcineurin (CaN), nuclear factor of activated T cells isoform C3 (NFATC3), glutathione peroxidase 4 (GPX4) and acyl-CoA synthase long chain family member 4 (ACSL4). Immunoprecipitation (IP) and luciferase reporter assays are performed to determine the interaction between NFATC3 and ACSL4. Both in vivo and in vitro experiments reveal that the V1aR-CaN-NFATC3 signaling pathway and ferroptosis are upregulated in HFs, which are verified by the elevated protein levels of V1aR, CaN, NFATC3 and ACSL4; reduced GPX4 protein level; and enhanced Fe 2+ and MDA levels. We further find that inhibiting NFATC3 by suppressing the V1aR/CaN/NFATC3 pathway via V1aR/CaN inhibitors or sh-NFATC3 not only alleviates HF but also inhibits AVP-induced ferroptosis. Mechanistically, sh-NFATC3 significantly reverses the increase in AVP-induced ACSL4 protein level, Fe 2+ concentration, and MDA level by directly interacting with ACSL4. Our results demonstrate that AVP enhances ACSL4 expression by activating the V1aR/CaN/NFATC3 pathway to induce ferroptosis, thus contributing to HF. This study may lead to the proposal of a novel therapeutic strategy for HF.

Non-coding RNAs in the pathophysiology of heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is the largest unmet clinical need in cardiovascular medicine. Despite decades of research, the treatment option for HFpEF is still limited, indicating our ongoing incomplete understanding on the underlying molecular mechanisms. Non-coding RNAs, comprising of microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), are non-protein coding RNA transcripts, which are implicated in various cardiovascular diseases. However, their role in the pathogenesis of HFpEF is unknown. Here, we discuss the role of miRNAs, lncRNAs and circRNAs that are involved in the pathophysiology of HFpEF, namely microvascular dysfunction, inflammation, diastolic dysfunction and cardiac fibrosis. We interrogated clinical evidence and dissected the molecular mechanisms of the ncRNAs by looking at the relevant in vivo and in vitro models that mimic the co-morbidities in patients with HFpEF. Finally, we discuss the potential of ncRNAs as biomarkers and potential novel therapeutic targets for future HFpEF treatment.

Apoptosis and long non-coding RNAs: Focus on their roles in Heart diseases

Heart disease is one of the principal death reasons around the world and there is a growing requirement to discover novel healing targets that have the potential to avert or manage these illnesses. On the other hand, apoptosis is a strongly controlled, cell removal procedure that has a crucial part in numerous cardiac problems, such as reperfusion injury, MI (myocardial infarction), consecutive heart failure, and inflammation of myocardium. Completely comprehending the managing procedures of cell death signaling is critical as it is the primary factor that influences patient mortality and morbidity, owing to cardiomyocyte damage. Indeed, the prevention of heart cell death appears to be a viable treatment approach for heart illnesses. According to current researches, a number of long non-coding RNAs cause the heart cells death via different methods that are embroiled in controlling the activity of transcription elements, the pathways that signals transmission within cells, small miRNAs, and the constancy of proteins. When there is too much cell death in the heart, it can cause problems like reduced blood flow, heart damage after restoring blood flow, heart disease in diabetics, and changes in the heart after reduced blood flow. Therefore, studying how lncRNAs control apoptosis could help us find new treatments for heart diseases. In this review, we present recent discoveries about how lncRNAs are involved in causing cell death in different cardiovascular diseases.

The regulation of circRNA and lncRNAprotein binding in cardiovascular diseases: Emerging therapeutic targets

Noncoding ribonucleic acids (ncRNAs) are a class of ribonucleic acids (RNAs) that carry cellular information and perform essential functions. This class encompasses various RNAs, such as small nuclear ribonucleic acids (snRNA), small interfering ribonucleic acids (siRNA) and many other kinds of RNA. Of these, circular ribonucleic acids (circRNAs) and long noncoding ribonucleic acids (lncRNAs) are two types of ncRNAs that regulate crucial physiological and pathological processes, including binding, in several organs through interactions with other RNAs or proteins. Recent studies indicate that these RNAs interact with various proteins, including protein 53, nuclear factor-kappa B, vascular endothelial growth factor, and fused in sarcoma/translocated in liposarcoma, to regulate both the histological and electrophysiological aspects of cardiac development as well as cardiovascular pathogenesis, ultimately leading to a variety of genetic heart diseases, coronary heart disease, myocardial infarction, rheumatic heart disease and cardiomyopathies. This paper presents a thorough review of recent studies on circRNA and lncRNAprotein binding within cardiac and vascular cells. It offers insight into the molecular mechanisms involved and emphasizes potential implications for treating cardiovascular diseases.

Circulatory long noncoding RNAs (circulatory-LNC-RNAs) as novel biomarkers and therapeutic targets in cardiovascular diseases: Implications for cardiovascular diseases complications

Cardiovascular diseases (CVDs) are a group of disorders with major global health consequences. The prevalence of CVDs continues to grow due to population-aging and lifestyle modifications. Non-coding RNAs (ncRNAs) as key regulators of cell signaling pathways have gained attention in the occurrence and development of CVDs. Exosomal-lncRNAs (exos-lncRNAs) are emerging biomarkers due to their high sensitivity and specificity, stability, accuracy and accessibility in the biological fluids. Recently, circulatory and exos-based-lncRNAs are emerging and novel bio-tools in various pathogenic conditions. It is worth mentioning that dysregulation of these molecules has been found in different types of CVDs. In this regard, we aimed to discuss the knowledge gaps and suggest research priorities regarding circulatory and exos-lncRNAs as novel bio-tools and therapeutic targets for CVDs.

Serum and glucocorticoid inducible kinase 1 modulates mitochondrial dysfunction and oxidative stress in doxorubicin-induced cardiomyocytes by regulating Hippo pathway via Neural precursor cell-expressed developmentally down-regulated 4 type 2

Doxorubicin (Dox) was reported to cause mitochondrial dysfunction and oxidative stress in cardiomyocytes, leading to cardiomyocyte apoptosis and ultimately heart failure. Serum and glucocorticoid inducible kinase 1 (SGK1) participates in the progression of various cardiovascular diseases. Thus, we aimed to explore the role and regulatory mechanism of SGK1 in Dox-induced cardiomyocyte injury. The expression of SGK1 was evaluated in blood samples of heart failure children, and in myocardial tissues and blood samples of Dox-induced rats. Subsequently, we treated cardiomyocytes with Dox in vitro. A gain-of-function assay was performed to assess the effects of SGK1 on mitochondrial dysfunction and oxidative stress in Dox-induced cardiomyocytes. Furthermore, the modulation of SGK1 on Neural precursor cell-expressed developmentally down-regulated 4 type 2 (NEDD4-2) expression and the subsequent Hippo pathway was validated. In our study, we found that SGK1 was downregulated in blood samples of heart failure children, as well as myocardial tissues and blood samples of Dox-induced rats. SGK1 overexpression alleviated the decreases of mitochondrial complex activity, mitochondrial membrane potential, adenosine triphosphate (ATP) content and ATP synthetase activity stimulated by Dox. Besides, SGK1 overexpression reversed the promoting effects of Dox on oxidative stress and apoptosis. Mechanistically, SGK1 overexpression inhibited the expression of NEDD4-2 and blocked the subsequent activation of Hippo pathway. NEDD4-2 overexpression or activation of Hippo reversed the protective effects of SGK1 overexpression on Dox-induced cardiomyocyte injury. In conclusion, our results revealed that SGK1 modulated mitochondrial dysfunction and oxidative stress in Dox-induced cardiomyocytes by regulating Hippo pathway via NEDD4-2.

Modulation of the long non-coding RNA Mir155hg by high, but not moderate, hydrostatic pressure in cartilage precursor cells

Osteoarthritis (OA) is the most common joint disease in older adults and is characterized by a gradual degradation of articular cartilage due to decreased cartilage matrix gene expression and increased expression of genes involved in protein degradation, apoptosis and inflammation. Due to the high water content of cartilage, one of the main physical stimuli sensed by chondrocytes is hydrostatic pressure. We previously showed that high pressure above 20 MPa induced gene expression changes in chondrocyte precursor cells similar to what is observed in OA. Micro-RNAs are small non-coding RNAs essential to many physiological and pathological process including OA. As the micro-RNA miR-155 has been found increased in OA chondrocytes, we investigated the effects of high pressure on the expression of the miR-155 host gene Mir155hg. The chondrocyte progenitor cell line ATDC5 was pressurized under hydrostatic pressure up to 25 MPa and the expression of Mir155hg or the resulting micro-RNAs were measured; pharmacological inhibitors were used to identify the signaling pathways involved in the regulation of Mir155hg. We found that Mir155hg is strongly and rapidly up-regulated by high, but not moderate, pressure in chondrocyte progenitor cells. This up-regulation likely involves the membrane channel pannexin-1 and several intracellular signaling molecules including PKC and Src. MiR-155-5p and -3p were also up-regulated by pressure though somewhat later than Mir155hg, and a set of known miR-155-5p target genes, including Ikbke, Smarca4 and Ywhae, was affected by pressure, suggesting that Mir155hg may have important roles in cartilage physiology.

LncRNA KCNQ1OT1: Molecular mechanisms and pathogenic roles in human diseases

Long non-coding RNAs (lncRNAs) exhibit a length more than 200 nucleotides and they are characterized by non-coding RNAs (ncRNA) not encoded into proteins. Over the past few years, the role and development of lncRNAs have aroused the rising attention of researchers. To be specific, KCNQ1OT1, the KCNQ1 opposite strand/antisense transcript 1, is clearly classified as a regulatory ncRNA. KCNQ1OT1 is capable of interacting with miRNAs, RNAs and proteins, thereby affecting gene expression and various cell functions (e.g., cell proliferation, migration, epithelial-mesenchymal transition (EMT), apoptosis, viability, autophagy and inflammation). KCNQ1OT1 is dysregulated in a wide range of human diseases (e.g., cardiovascular disease, cancer, diabetes, osteoarthritis, osteoporosis and cataract), and it is speculated to act as a therapeutic target for treating various human diseases. On the whole, this review aims to explore the biological functions, underlying mechanisms and pathogenic roles of KCNQ1OT1 in human diseases.

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.

Long noncoding RNA NONMMUT015745 inhibits doxorubicin-mediated cardiomyocyte apoptosis by regulating Rab2A-p53 axis

Doxorubicin (DOX) is an efficacious and widely used drug for human malignancy treatment, but its clinical application is limited due to side effects, especially cardiotoxicity. Our present study revealed that DOX could induce apoptosis in cardiomyocytes. Herein, we screened the dysregulated long noncoding RNAs (lncRNAs) in DOX-treated cardiomyocytes. Notably, overexpression of lncRNA NONMMUT015745 (lnc5745) could alleviate DOX-induced cardiomyocyte apoptosis both in vitro and in vivo. Conversely, silencing lnc5745 promotes cardiomyocyte apoptosis. Moreover, Rab2A, a direct target of lnc5745, possesses a protective effect in DOX-induced cardiotoxicity once knocked down. Importantly, we verified that the p53-related apoptotic signalling pathway was responsible for the lnc5745-mediated protective role against DOX-induced cardiomyocyte apoptosis. Mechanistically, Rab2A interacts with p53 and phosphorylated p53 on Ser 33 (p53 (Phospho-Ser 33)), promotes p53 phosphorylation, thereby activating the apoptotic pathway. Taken together, our results suggested that lnc5745 protects against DOX-induced cardiomyocyte apoptosis through suppressing Rab2A expression, modifying p53 phosphorylation, thereby regulating p53-related apoptotic signalling pathway. Our findings establish the functional mode of the lnc5745-Rab2A-p53 axis in DOX-induced cardiotoxicity. The development of new strategies targeting the lnc5745-Rab2A-p53 axis could attenuate DOX-induced cardiotoxicity, which is beneficial to its clinical anti-tumour application.

KLHL38 facilitates STS-induced apoptosis in HL-1 cells via myocardin degradation

Cardiac apoptosis has been identified as one of the main precipitating factors of heart failure (HF) throughout the whole course of progressive disease. Limited to the lack of diagnostic markers and effective drug targets, cardiac apoptosis is still a major clinical challenge. Here, we reveal a potential novel therapeutic target for cardiac apoptosis. In the cause of the study, we found that KLHL38 was highly expressed in cardiac tissue of heart failure patients via GEO data-mining, which was further verified in the heart tissue of TAC mice. Meanwhile, the expression of KLHL38 is negatively correlated with myocardin protein level, which is a key cardiac apoptosis regulator. The KLHL38 overexpression obviously promoted cardiomyocyte apoptosis treated with staurosporine (STS) by facilitation of myocardin's ubiquitylation and subsequent proteasomal degradation. These findings reveal a new therapeutic target which may provide a new theoretical foundation for the treatment of myocardial apoptosis in clinical practice.

Pyroptosis and Its Regulation in Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DbCM) is a prevalent disease, characterized by contractile dysfunction and left ventricular hypertrophy. Patients with DbCM have high morbidity and mortality worldwide. Recent studies have identified that pyroptosis, a kind of cell death, could be induced by hyperglycemia involved in the formation of DbCM. This review summarizes the regulatory mechanisms of pyroptosis in DbCM, including NOD-like receptor3, AIM2 inflammasome, long non-coding RNAs, microRNAs, circular RNA, autophagy, and some drugs.

Transcriptome analysis of long noncoding RNAs reveals their potential roles in anthracycline-induced cardiotoxicity

Aims

Anthracyclines (ANTs) are essential chemotherapeutic agents; however, their adverse effects can lead to heart failure in cancer survivors. While long non-coding RNAs (lncRNAs) have become new players in cellular processes, there is limited knowledge on lncRNA expression related to anthracyclines-induced cardiotoxicity. This study investigates the lncRNA profiles in human cardiac microtissues exposed to 3 popular ANTs, namely doxorubicin, epirubicin, and idarubicin, as well as in heart biopsies from ANT-treated patients.

Methods and results

The in vitro microtissues were exposed to each ANT at 2 doses over 2 weeks; the transcriptome data was collected at 7 time points. The human biopsies were collected from heart failure patients who underwent ANT treatment and control subjects. Over 100 lncRNAs were differentially expressed in each in vitro ANT treatment condition compared to control samples; 16 of them were differentially expressed across all ANT-treated conditions. The lncRNA databases and literature revealed insight on how these lncRNAs relate to heart failure and cellular functions. For instance, H19 and RMRP are involved in heart failure progression, while BDNF-AS is a cardiomyocyte damage-associated gene; SNHG7 is a cardiac hypertrophy regulator. PCAT19 can promote the miR‐182/PDK4 axis and modulate p53 expression, whereas SNHG29 can regulate the Wnt/β-catenin signaling pathway via the miR-223–3p/CTNND1 axis. Other lncRNAs, which were only differentially expressed in particular ANT-treated conditions, are also involved in cardiomyocyte damage and heart failure disease. The alterations of these lncRNA expressions in the in vitro cardiac tissue were also affirmed by similar changes in the human biopsies.

Conclusion

This study revealed several lncRNAs that can be potential biomarkers or targets for further ANT-induced cardiotoxicity investigation, according to the transcriptome in both human cardiac microtissues expose to ANTs as well as in heart biopies form ANT-treated patients. Especially, H19 lncRNA showed its contribution to on-target toxicity, in which it is involved in both chemoresistance and cardiotoxic mechanism.

Long Noncoding RNAs Involved in Cardiomyocyte Apoptosis Triggered by Different Stressors

Cardiomyocytes are essential to maintain the normal cardiac function. Ischemia, hypoxia, and drug stimulation can induce pathological apoptosis of cardiomyocytes which eventually leads to heart failure, arrhythmia, and other cardiovascular diseases. Understanding the molecular mechanisms that regulate cardiomyocyte apoptosis is of great significance for the prevention and treatment of cardiovascular diseases. In recent years, more and more evidences reveal that long noncoding RNAs (lncRNAs) play important regulatory roles in myocardial cell apoptosis. They can modulate the expression of apoptosis-related genes at post-transcriptional level by altering the translation efficacy of target mRNAs or functioning as a precursor for miRNAs or competing for miRNA-mediated inhibition. Moreover, reversing the abnormal expression of lncRNAs can attenuate and even reverse the pathological apoptosis of cardiomyocytes. Therefore, apoptosis-related lncRNAs may become a potential new field for studying cardiomyocyte apoptosis and provide new ideas for the treatment of cardiovascular diseases.

Establishment and analysis of the lncRNA-miRNA-mRNA network based on competitive endogenous RNA identifies functional genes in heart failure

Heart failure (HF), a common disease in adults, accounts for significantly global morbidity and mortality. Due to population aging, therapeutic progression in acute cardiovascular events, the prevalence of HF is increasing, in spite of the efficacy of multiple therapies for HF patients with decreased ejection fraction. Despite great progress in the underlying molecular mechanisms, it remains incompletely clear of the function of competing endogenous RNA (ceRNA) network in HF pathogenesis. Herein, we established an HF-related ceRNA network on the basis of differentially expressed long noncoding RNAs (lncRNAs), microRNAs (miRNAs) as well as mRNAs from GSE136547 and GSE124401 datasets. In brief, the ceRNA network composed of 58 mRNA nodes, 5 miRNA nodes, 82 lncRNA nodes as well as 252 edges. In addition, three lncRNAs (KCNQ1OT1, XIST and AC010336) with higher node degrees than other lncRNAs were chosen as hub nodes. At the same time, we have established five subnetwork of miR-17-5p, miR-20b-5p, miR-107, miR-125a-5p and miR-140-5p centered ceRNA. Pathway analysis revealed the enrichment of ceRNA network in cell cycle pathways. Collectively, our research sheds new lights on the essential functions of ceRNA network in HF development, which also suggests possible application of these hub nodes as diagnostic biomarkers as well as therapeutic targets.

Fus knockdown inhibits the profibrogenic effect of cardiac fibroblasts induced by angiotensin II through targeting Pax3 thereby regulating TGF-β1/Smad pathway

The Angiotensin II/transforming growth factor-β1 (AngII/TGF-β1) signal axis is an important regulatory pathway for atrial fibrosis, which can contribute to atrial fibrillation (AF). Fused in sarcoma (FUS) was recently found to regulate cardiac diseases. This study aimed to investigate whether FUS could regulate AngII induced fibrosis and uncover the possible mechanisms. The expression of FUS in AF patients and AngII-induced cardiac fibroblasts was measured by RT-qPCR and western blot assays. Fus was silenced in cells using short hairpin RNA (shRNA), then cell proliferation, migration, collagen synthesis and TGF-β1/Smad signaling were detected by CCK-8, wound healing and western blot assays, respectively. The possible target for Fus was predicted by searching Starbase database and verified by RNA-binding protein immunoprecipitation (RIP) and RNA pull down. Cells were overexpressed with Pax3 in the presence of Fus silence and AngII stimulation, then the above cellular processes were further evaluated. Results showed that FUS was upregulated in AF patients and AngII-induced cardiac fibroblasts. Fus knockdown inhibited AngII-enhanced cell proliferation, migration, collagen synthesis and TGF-β1/Smad signaling activation. Furthermore, Fus functions as an RNA-binding protein to bind to Pax3 mRNA and positively regulate its expression. Further studies demonstrated that Pax3 overexpression canceled the above effects of Fus knockdown on cell proliferation, migration, collagen synthesis, and TGF-β1/Smad signaling activation in AngII-induced cells. In conclusion, Fus could target Pax3 to increase the pro-fibrotic effect of AngII in cardiac fibroblasts via activating TGF-β1/Smad signaling. Knockdown of Fus/Pax3 axis may provide a potential therapy for relieving AF.