BCL-6 promotes the methylation of miR-34a by recruiting EZH2 and upregulating CTRP9 to protect ischemic myocardial injury

N-terminal domain of CTRP9 promotes cardiac fibroblast activation in myocardial infarction via Rap1/Mek/Erk pathway

BACKGROUND

In developed nations, myocardial infarction (MI) is one of the main causes of morbidity and mortality, resulting in a significant economic burden and becoming a global public health problem. C1q/tumor necrosis factor-related protein 9 (CTRP9) is a secreted protein comprising a variable domain, a collagenous region, and a C-terminal trimerizing globular C1q (gC1q) domain. In vivo, the full-length CTRP9 (fCTRP9) can be cleaved into the globular domain of CTRP9 (gCTRP9). Here, we tested the cardio-protective impacts of fCTRP9, gCTRP9, and N-terminal domain, including the variable and collagenous domain, of CTRP9 (nCTRP9) in the context of MI.

METHODS

Studies comparing the protective properties of fCTRP9 and gCTRP9 against MI in mice hearts were performed both in vitro and in vivo. The role of matrix metalloproteinase-9 (MMP9) in CTRP9 cleavage was examined, and the effects of different CTRP9 domains on cardiac fibrosis and cardiac fibroblast (CF) activation were investigated.

RESULTS

gCTRP9 exerted better protective effects than fCTRP9 against MI, demonstrating superior anti-apoptotic and anti-fibrotic properties. fCTRP9 was cleaved by MMP9, resulting in gCTRP9 and nCTRP9. MMP9 overexpression enhanced the cardioprotective effects of fCTRP9, while nCTRP9 supplementation aggravated cardiac fibrosis in MI mice. Mechanistically, nCTRP9 activated CFs via an increase in Rap1 expression and MEK 1/2 and ERK1/2 phosphorylation.

CONCLUSIONS

Different domains of CTRP9 have distinct cardioprotective effects. gCTRP9 shows beneficial effects, while nCTRP9 promotes cardiac fibrosis. These findings highlight the importance of CTRP9 in cardiac function regulation and suggest prospective therapeutic options for MI treatment.

Fibroblast-derived miR-425-5p alleviates cardiac remodelling in heart failure via inhibiting the TGF-β1/Smad signalling

The pathological activation of cardiac fibroblasts (CFs) plays a crucial role in the development of pressure overload-induced cardiac remodelling and subsequent heart failure (HF). Growing evidence demonstrates that multiple microRNAs (miRNAs) are abnormally expressed in the pathophysiologic process of cardiovascular diseases, with miR-425 recently reported to be potentially involved in HF. In this study, we aimed to investigate the effects of fibroblast-derived miR-425-5p in pressure overload-induced HF and explore the underlying mechanisms. C57BL/6 mice were injected with a recombinant adeno-associated virus specifically designed to overexpress miR-425-5p in CFs, followed by transverse aortic constriction (TAC) surgery. Neonatal mouse CFs (NMCFs) were transfected with miR-425-5p mimics and subsequently stimulated with angiotensin II (Ang II). We found that miR-425-5p levels were significantly downregulated in HF mice and Ang II-treated NMCFs. Notably, fibroblast-specific overexpression of miR-425-5p markedly inhibited the proliferation and differentiation of CFs, thereby alleviating myocardial fibrosis, cardiac hypertrophy and systolic dysfunction. Mechanistically, the cardioprotective actions of miR-425-5p may be achieved by targeting the TGF-β1/Smad signalling. Interestingly, miR-425-5p mimics-treated CFs could also indirectly affect cardiomyocyte hypertrophy in this course. Together, our findings suggest that fibroblast-derived miR-425-5p mitigates TAC-induced HF, highlighting miR-425-5p as a potential diagnostic and therapeutic target for treating HF patients.

DEAD-box helicase 17 (DDX17) protects cardiac function by promoting mitochondrial homeostasis in heart failure

DEAD-box helicase 17 (DDX17) is a typical member of the DEAD-box family with transcriptional cofactor activity. Although DDX17 is abundantly expressed in the myocardium, its role in heart is not fully understood. We generated cardiomyocyte-specific Ddx17-knockout mice (Ddx17-cKO), cardiomyocyte-specific Ddx17 transgenic mice (Ddx17-Tg), and various models of cardiomyocyte injury and heart failure (HF). DDX17 is downregulated in the myocardium of mouse models of heart failure and cardiomyocyte injury. Cardiomyocyte-specific knockout of Ddx17 promotes autophagic flux blockage and cardiomyocyte apoptosis, leading to progressive cardiac dysfunction, maladaptive remodeling and progression to heart failure. Restoration of DDX17 expression in cardiomyocytes protects cardiac function under pathological conditions. Further studies showed that DDX17 can bind to the transcriptional repressor B-cell lymphoma 6 (BCL6) and inhibit the expression of dynamin-related protein 1 (DRP1). When DDX17 expression is reduced, transcriptional repression of BCL6 is attenuated, leading to increased DRP1 expression and mitochondrial fission, which in turn leads to impaired mitochondrial homeostasis and heart failure. We also investigated the correlation of DDX17 expression with cardiac function and DRP1 expression in myocardial biopsy samples from patients with heart failure. These findings suggest that DDX17 protects cardiac function by promoting mitochondrial homeostasis through the BCL6-DRP1 pathway in heart failure.

Role of transcriptional cofactors in cardiovascular diseases

Cardiovascular disease is a main cause of mortality in the world and the highest incidence of all diseases. However, the mechanism of the pathogenesis of cardiovascular disease is still unclear, and we need to continue to explore its mechanism of action. The occurrence and development of cardiovascular disease is significantly associated with genetic abnormalities, and gene expression is affected by transcriptional regulation. In this complex process, the protein-protein interaction promotes the RNA polymerase II to the initiation site. And in this process of transcriptional regulation, transcriptional cofactors are responsible for passing cues from enhancers to promoters and promoting the binding of RNA polymerases to promoters, so transcription cofactors playing a key role in gene expression regulation. There is growing evidence that transcriptional cofactors play a critical role in cardiovascular disease. Transcriptional cofactors can promote or inhibit transcription by affecting the function of transcription factors. It can affect the initiation and elongation process of transcription by forming complexes with transcription factors, which are important for the stabilization of DNA rings. It can also act as a protein that interacts with other proteins to affect the expression of other genes. Therefore, the aim of this overview is to summarize the effect of some transcriptional cofactors such as BRD4, EP300, MED1, EZH2, YAP, SIRT6 in cardiovascular disease and to provide a promising therapeutic strategy for the treatment of cardiovascular disease.

Chromatin modifiers in human disease: from functional roles to regulatory mechanisms

The field of transcriptional regulation has revealed the vital role of chromatin modifiers in human diseases from the beginning of functional exploration to the process of participating in many types of disease regulatory mechanisms. Chromatin modifiers are a class of enzymes that can catalyze the chemical conversion of pyrimidine residues or amino acid residues, including histone modifiers, DNA methyltransferases, and chromatin remodeling complexes. Chromatin modifiers assist in the formation of transcriptional regulatory circuits between transcription factors, enhancers, and promoters by regulating chromatin accessibility and the ability of transcription factors to acquire DNA. This is achieved by recruiting associated proteins and RNA polymerases. They modify the physical contact between cis-regulatory factor elements, transcription factors, and chromatin DNA to influence transcriptional regulatory processes. Then, abnormal chromatin perturbations can impair the homeostasis of organs, tissues, and cells, leading to diseases. The review offers a comprehensive elucidation on the function and regulatory mechanism of chromatin modifiers, thereby highlighting their indispensability in the development of diseases. Furthermore, this underscores the potential of chromatin modifiers as biomarkers, which may enable early disease diagnosis. With the aid of this paper, a deeper understanding of the role of chromatin modifiers in the pathogenesis of diseases can be gained, which could help in devising effective diagnostic and therapeutic interventions.

Advances in bi-directional relationships for EZH2 and oxidative stress

Over the past two decades, polycomb repressive complex 2(PRC2) has emerged as a vital repressive complex in overall cell fate determination. In mammals, enhancer of zeste homolog 2 (EHZ2), which is the core component of PRC2, has also been recognized as an important regulator of inflammatory, redox, tumorigenesis and damage repair signalling networks. To exert these effects, EZH2 must regulate target genes epigenetically or interact directly with other gene expression-regulating factors, such as LncRNAs and microRNAs. Our review provides a comprehensive summary of research advances, discoveries and trends regarding the regulatory mechanisms between EZH2 and reactive oxygen species (ROS). First, we outline novel findings about how EZH2 regulates the generation of ROS at the molecular level. Then, we summarize how oxidative stress controls EHZ2 alteration (upregulation, downregulation, or phosphorylation) via various molecules and signalling pathways. Finally, we address why EZH2 and oxidative stress have an undefined relationship and provide potential future research ideas.

MicroRNA Expression Profile in Bone Marrow and Lymph Nodes in B-Cell Lymphomas

Hodgkin's lymphomas (HL) and the majority of non-Hodgkin's lymphomas (NHL) derive from different stages of B-cell differentiation. MicroRNA (miRNA) expression profiles change during lymphopoiesis. Thus, miRNA expression analysis can be used as a reliable diagnostic tool to differentiate tumors. In addition, the identification of miRNA's role in lymphopoiesis impairment is an important fundamental task. The aim of this study was to analyze unique miRNA expression profiles in different types of B-cell lymphomas. We analyzed the expression levels of miRNA-18a, -20a, -96, -182, -183, -26b, -34a, -148b, -9, -150, -451a, -23b, -141, and -128 in lymph nodes (LNs) in the following cancer samples: HL (n = 41), diffuse large B-cell lymphoma (DLBCL) (n = 51), mantle cell lymphoma (MCL) (n = 15), follicular lymphoma (FL) (n = 12), and lymphadenopathy (LA) (n = 37), as well as bone marrow (BM) samples: HL (n = 11), DLBCL (n = 42), MCL (n = 14), FL (n = 16), and non-cancerous blood diseases (NCBD) (n = 43). The real-time RT-PCR method was used for analysis. An increase in BM expression levels of miRNA-26b, -150, and -141 in MCL (p < 0.01) and a decrease in BM levels of the miR-183-96-182 cluster and miRNA-451a in DLBCL (p < 0.01) were observed in comparison to NCBD. We also obtained data on increased LN levels of the miR-183-96-182 cluster in MCL (p < 0.01) and miRNA-18a, miRNA-96, and miRNA-9 in FL (p < 0.01), as well as decreased LN expression of miRNA-150 in DLBCL (p < 0.01), and miRNA-182, miRNA-150, and miRNA-128 in HL (p < 0.01). We showed that miRNA expression profile differs between BM and LNs depending on the type of B-cell lymphoma. This can be due to the effect of the tumor microenvironment.

HSP90-Dependent Upregulation of EZH2 Promotes Hypoxia/Reoxygenation-Induced Pyroptosis by Inhibiting miR-22 in Endothelial Cells

Objective

Endothelial cell pyroptosis induced by hypoxia/reoxygenation (H/R) plays a key role in the pathogenesis of myocardial infarction (MI). However, the underlying mechanism is not clearly elucidated.

Methods

Human umbilical vein endothelial cells (HUVECs) exposed to H/R acted as in vitro model to investigate the mechanism of H/R-induced endothelial cell pyroptosis. CCK-8 assays were performed to investigate the viability of HUVECs. Calcein-AM/PI staining was carried out to quantify the death of HUVECs. The expression level of miR-22 was measured by RT-qPCR. The protein expression levels of zeste 2 polycomb repressive complex 2 subunit (EZH2), NLRP3, cleaved caspase-1 (c-caspase-1), GSDMD-N and heat shock protein 90 (HSP90) were measured by Western blot. Levels of IL-1β and IL-18 in culture medium were detected by ELISA. The intracellular localization of EZH2 was detected by immunofluorescence staining. Chromatin immunoprecipitation (ChIP) assay was used to detect the enrichment of EZH2 and H3K27me3 in the miR-22 promoter region. The binding between miR-22 and NLRP3 in HUVECs was confirmed by the dual luciferase assay. Reciprocal coimmunoprecipitation was conducted to detect the direct interaction between HSP90 and EZH2.

Results

H/R increased EZH2 expression, and the EZH2 siRNA could inhibit H/R-induced pyroptosis in HUVECs. H/R reduced miR-22 expression, which was reversed by EZH2 siRNA. Silencing of miR-22 by its inhibitor reversed EZH2 siRNA-induced pyroptosis inhibition in H/R-exposed HUVECs. Upregulation of miR-22 by its mimic suppressed EZH2 overexpression-enhanced pyroptosis in H/R-exposed HUVECs. ChIP assay confirmed that EZH2 bound to the miR-22 promoter region and repressed miR-22 expression through H3K27me3. Furthermore, luciferase reporter assay indicated that NLRP3 was a direct target of miR- 22 in HUVECs. Finally, HSP90 siRNA inhibited H/R-induced EZH2 expression, miR-22 downregulation, and pyroptosis in HUVECs.

Conclusion

H/R induces pyroptosis via the HSP90/EZH2/miR-22/NLRP3 signaling axis in endothelial cells.

MicroRNA in the Diagnosis and Treatment of Doxorubicin-Induced Cardiotoxicity

Doxorubicin (DOX), a broad-spectrum chemotherapy drug, is widely applied to the treatment of cancer; however, DOX-induced cardiotoxicity (DIC) limits its clinical therapeutic utility. However, it is difficult to monitor and detect DIC at an early stage using conventional detection methods. Thus, sensitive, accurate, and specific methods of diagnosis and treatment are important in clinical practice. MicroRNAs (miRNAs) belong to non-coding RNAs (ncRNAs) and are stable and easy to detect. Moreover, miRNAs are expected to become biomarkers and therapeutic targets for DIC; thus, there are currently many studies focusing on the role of miRNAs in DIC. In this review, we list the prominent studies on the diagnosis and treatment of miRNAs in DIC, explore the feasibility and difficulties of using miRNAs as diagnostic biomarkers and therapeutic targets, and provide recommendations for future research.

Identification and validation of senescence-related genes in circulating endothelial cells of patients with acute myocardial infarction

Background

Acute myocardial infarction (AMI) is the main clinical cause of death and cardiovascular disease and thus has high rates of morbidity and mortality. The increase in cardiovascular disease with aging is partly the result of vascular endothelial cell senescence and associated vascular dysfunction. This study was performed to identify potential key cellular senescence-related genes (SRGs) as biomarkers for the diagnosis of AMI using bioinformatics.

Methods

Using the CellAge database, we identified cellular SRGs. GSE66360 and GSE48060 for AMI patients and healthy controls and GSE19322 for mice were downloaded from the Gene Expression Omnibus (GEO) database. The GSE66360 dataset was divided into a training set and a validation set. The GSE48060 dataset was used as another validation set. The GSE19322 dataset was used to explore the evolution of the screened diagnostic markers in the dynamic process of AMI. Differentially expressed genes (DEGs) of AMI were identified from the GSE66360 training set. Differentially expressed senescence-related genes (DESRGs) selected from SRGs and DEGs were analyzed using Gene Ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, and protein-protein interaction (PPI) networks. Hub genes in DESRGs were selected based on degree, and diagnostic genes were further screened by gene expression and receiver operating characteristic (ROC) curve. Finally, a miRNA-gene network of diagnostic genes was constructed and targeted drug prediction was performed.

Results

A total of 520 DEGs were screened from the GSE66360 training set, and 279 SRGs were identified from the CellAge database. The overlapping DEGs and SRGs constituted 14 DESRGs, including 4 senescence suppressor genes and 10 senescence inducible genes. The top 10 hub genes, including FOS, MMP9, CEBPB, CDKN1A, CXCL1, ETS2, BCL6, SGK1, ZFP36, and IGFBP3, were screened. Furthermore, three diagnostic genes were identified: MMP9, ETS2, and BCL6. The ROC analysis showed that the respective area under the curves (AUCs) of MMP9, ETS2, and BCL6 were 0.786, 0.848, and 0.852 in the GSE66360 validation set and 0.708, 0.791, and 0.727 in the GSE48060 dataset. In the GSE19322 dataset, MMP9 (AUC, 0.888) and ETS2 (AUC, 0.929) had very high diagnostic values in the early stage of AMI. Finally, based on these three diagnostic genes, we found that drugs such as acetylcysteine and genistein may be targeted for the treatment of age-related AMI.

Conclusion

The results of this study suggest that cellular SRGs might play an important role in AMI. MMP9, ETS2, and BCL6 have potential as specific biomarkers for the early diagnosis of AMI.

Mechanical stretch aggravates vascular smooth muscle cell apoptosis and vascular remodeling by downregulating EZH2

BACKGROUND

Enhancer of zeste homolog 2 (EZH2) was recently found to play an important role in cardiovascular disease. However, the role of EZH2 in vascular remodeling induced by mechanical stretch is poorly understood. The aim of the present work was to investigate the role of EZH2 in regulating smooth muscle cell function through mechanical stretch assays and to explore the underlying mechanisms.

METHODS

WT C57BL/6 J mice underwent sham surgery or abdominal aortic constriction. The level of EZH2 expression was determined by Western blotting and immunohistochemical staining. We demonstrated the thickness of vascular remodeling by HE staining. JASPAR was used to predict transcription factors that could affect EZH2. Chromatin immunoprecipitation was used to substantiate the DNAprotein interactions. Promoter luciferase assays were performed to demonstrate the activity of the transcription factors.

RESULTS

We found that in vivo, AAC significantly reduced EZH2 protein levels in the thoracic aorta. Smooth muscle-specific overexpression of EZH2 was sufficient to attenuate the AAC-induced reduction in trimethylation of Lys-27 in histone 3 and thickening of the arterial media. Administration of GSK-J4 (an inhibitor of H3K27me3 demethylase) induced the same effects. In addition, we found that mechanical stretch regulated the expression of EZH2 through the Yes-associated protein (YAP)- transcriptional factor TEA domain 1 (TEAD) pathway. TEAD1 bound directly to the promoter of EZH2, and blocking the YAP-TEAD1 interaction inhibited EZH2 downregulation due to mechanical stretch.

CONCLUSION

This study reveals that mechanical stretch downregulates EZH2 through the YAP-TEAD1 pathway, thereby aggravating smooth muscle cell apoptosis and vascular remodeling.

Construction of Novel Gene Signature-Based Predictive Model for the Diagnosis of Acute Myocardial Infarction by Combining Random Forest With Artificial Neural Network

Background

Acute myocardial infarction (AMI) is one of the most common causes of mortality around the world. Early diagnosis of AMI contributes to improving prognosis. In our study, we aimed to construct a novel predictive model for the diagnosis of AMI using an artificial neural network (ANN), and we verified its diagnostic value via constructing the receiver operating characteristic (ROC).

Methods

We downloaded three publicly available datasets (training sets GSE48060, GSE60993, and GSE66360) from Gene Expression Omnibus (GEO) database, and differentially expressed genes (DEGs) were identified between 87 AMI and 78 control samples. We applied the random forest (RF) and ANN algorithms to further identify novel gene signatures and construct a model to predict the possibility of AMI. Besides, the diagnostic value of our model was further validated in the validation sets GSE61144 (7 AMI patients and 10 controls), GSE34198 (49 AMI patients and 48 controls), and GSE97320 (3 AMI patients and 3 controls).

Results

A total of 71 DEGs were identified, of which 68 were upregulated and 3 were downregulated. Firstly, 11 key genes in 71 DEGs were screened with RF classifier for the classification of AMI and control samples. Then, we calculated the weight of each key gene using ANN. Furthermore, the diagnostic model was constructed and named neuralAMI, with significant predictive power (area under the curve [AUC] = 0.980). Finally, our model was validated with the independent datasets GSE61144 (AUC = 0.900), GSE34198 (AUC = 0.882), and GSE97320 (AUC = 1.00).

Conclusion

Machine learning was used to develop a reliable predictive model for the diagnosis of AMI. The results of our study provide potential gene biomarkers for early disease screening.

Targeting the microRNA-34a as a Novel Therapeutic Strategy for Cardiovascular Diseases

Cardiovascular diseases (CVDs) are still the main cause of morbidity and mortality worldwide and include a group of disorders varying from vasculature, myocardium, arrhythmias and cardiac development. MicroRNAs (miRs) are endogenous non-coding RNAs with 18–23 nucleotides that regulate gene expression. The miR-34 family, including miR-34a/b/c, plays a vital role in the regulation of myocardial physiology and pathophysiological processes. Recently, miR-34a has been implicated in cardiovascular fibrosis, dysfunction and related cardiovascular disorders as an essential regulator. Interestingly, there is a pivotal link among miR-34a, cardiovascular fibrosis, and Smad4/TGF-β1 signaling. Notably, both loss-of-function and gain-of-function approaches identified the critical roles of miR-34a in cardiovascular apoptosis, autophagy, inflammation, senescence and remodeling by modulating multifunctional signaling pathways. In this article, we focus on the current understanding of miR-34a in biogenesis, its biological effects and its implications for cardiac pathologies including myocardial infarction, heart failure, ischaemia reperfusion injury, cardiomyopathy, atherosclerosis, hypertension and atrial fibrillation. Thus, further understanding of the effects of miR-34a on cardiovascular diseases will aid the development of effective interventions. Targeting for miR-34a has emerged as a potential therapeutic target for cardiovascular dysfunction and related diseases.

Correlations between vitronectin, miR-520, and miR-34 in patients with stenosis of coronary arteries

BACKGROUND

In-stent restenosis usually occurs by platelet activation, neointima formation, VSMC migration, and proliferation in the position of the vessel stent. The monocytes have a magnificent role in neointimal hyperplasia since these cells recruit to the site of vessel injury through chemokines and other secretion proteins. This study is focused on the investigation of vitronectin, miR-193, miR-34, and miR-520 expression levels in PBMCs isolated from stenosed patients.

METHODS

A total of sixty subjects undergoing coronary artery angiography containing patients with stent no restenosis (n = 20), in-stent restenosis (n = 20), and healthy participants (n = 20) participated in the study. The vitronectin, miR-193, miR-34, and miR-520 expression levels were measured by the RT-qPCR technique. Data were analyzed by SPSS software.

RESULTS

The vitronectin, miR-34, and miR-520 expression levels changed significantly in patients with vessel in-stent restenosis (p = 0.02, p = 0.02, and p = 0.01, respectively). Furthermore, there were inverse correlations between the expression levels of vitronectin gene and miR-34 (r =  - 0.44, p = 0.04) as well as miR-520 (r =  - 0.5, p=0.01).

CONCLUSIONS

The molecular events in the vessel stenosis may be affected by targeting vitronectin with miR-520 and miR-34.