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.

PINK1/Parkin-mediated mitophagy in cardiovascular disease: From pathogenesis to novel therapy.

Cardiovascular disease(CVD)is one of the predominant causes of death and morbidity. Mitochondria play a key role in maintaining cardiac energy metabolism. However, mitochondrial dysfunction leads to excessive production of ROS, resulting in oxidative damage to cardiomyocytes and contributing to a variety of cardiovascular diseases. In such a case, the clearance of impaired mitochondria is necessary. Currently, most studies have indicated an essential role for mitophagy in maintaining cardiac homeostasis and regulating CVD-related metabolic transition. Recent studies have implicated that PTEN-induced putative kinase 1 (PINK1)/Parkin-mediated mitophagy has been implicated in maintaining cardiomyocyte homeostasis. Here, we discuss the physiological and pathological roles of PINK1/Parkin-mediated mitophagy in the cardiovascular system, as well as potential therapeutic strategies based on PINK1/Parkin-mediated mitophagy modulation, which are of great significance for the prevention and treatment of cardiovascular diseases.

Integrated Bioinformatics-Based Analysis of Hub Genes and the Mechanism of Immune Infiltration Associated With Acute Myocardial Infarction.

Background: Acute myocardial infarction (AMI) is a fatal disease that causes high morbidity and mortality. It has been reported that AMI is associated with immune cell infiltration. Now, we aimed to identify the potential diagnostic biomarkers of AMI and uncover the immune cell infiltration profile of AMI. Methods: From the Gene Expression Omnibus (GEO) data set, three data sets (GSE48060, GSE60993, and GSE66360) were downloaded. Differentially expressed genes (DEGs) from AMI and healthy control samples were screened. Furthermore, DEGs were performed via gene ontology (GO) functional and kyoto encyclopedia of genes and genome (KEGG) pathway analyses. The Gene set enrichment analysis (GSEA) was used to analyze GO terms and KEGG pathways. Utilizing the Search Tool for Retrieval of Interacting Genes/Proteins (STRING) database, a protein-protein interaction (PPI) network was constructed, and the hub genes were identified. Then, the receiver operating characteristic (ROC) curves were constructed to analyze the diagnostic value of hub genes. And, the diagnostic value of hub genes was further validated in an independent data set GSE61144. Finally, CIBERSORT was used to represent the compositional patterns of the 22 types of immune cell fractions in AMI. Results: A total of 71 DEGs were identified. These DEGs were mainly enriched in immune response and immune-related pathways. Toll-like receptor 2 (TLR2), interleukin-1B (IL1B), leukocyte immunoglobulin-like receptor subfamily B2 (LILRB2), Fc fragment of IgE receptor Ig (FCER1G), formyl peptide receptor 1 (FPR1), and matrix metalloproteinase 9 (MMP9) were identified as diagnostic markers with the value of p < 0.05. Also, the immune cell infiltration analysis indicated that TLR2, IL1B, LILRB2, FCER1G, FPR1, and MMP9 were correlated with neutrophils, monocytes, resting natural killer (NK) cells, gamma delta T cells, and CD4 memory resting T cells. The fractions of monocytes and neutrophils were significantly higher in AMI tissues than in control tissues. Conclusion: TLR2, IL1B, LILRB2, FCER1G, FPR1, and MMP9 are involved in the process of AMI, which can be used as molecular biomarkers for the screening and diagnosis of AMI. In addition, the immune system plays a vital role in the occurrence and progression of AMI.

Single-Cell Sequencing Revealed Pivotal Genes Related to Prognosis of Myocardial Infarction Patients.

Objectives: Myocardial infarction (MI) is a common cardiovascular disease. Histopathology is a main molecular characteristic of MI, but often, differences between various cell subsets have been neglected. Under this premise, MI-related molecular biomarkers were screened using single-cell sequencing. Methods: This work examined immune cell abundance in normal and MI samples from GSE109048 and determined differences in the activated mast cells and activated CD4 memory T cells, resting mast cells. Weighted gene coexpression network analysis (WGCNA) demonstrated that activated CD4 memory T cells were the most closely related to the turquoise module, and 10 hub genes were screened. Single-cell sequencing data (scRNA-seq) of MI were examined. We used t-distributed stochastic neighbor embedding (t-SNE) for cell clustering. Results: We obtained 8 cell subpopulations, each of which had different marker genes. 7 out of the 10 hub genes were detected by single-cell sequencing analysis. The expression quantity and proportion of the 7 genes were different in 8 cell clusters. Conclusion: In general, our study revealed the immune characteristics and determined 7 prognostic markers for MI at the single-cell level, providing a new understanding of the molecular characteristics and mechanism of MI.

MiR-100-5p regulates cardiac hypertrophy through activation of autophagy by targeting mTOR.

Autophagy has been proved to play a vital role in cardiac hypertrophy. The present study was designed to investigate the relationship between miR-100-5p and autophagy in the development of cardiac hypertrophy. Here, miR-100-5p expression was detected in abdominal aortic coarctation (AAC)-induced cardiac hypertrophy rats and Angiotensin II (Ang II)-stimulated cardiomyocytes. In vitro and in vivo experiments were performed to explore the function of miR-100-5p on autophagy and cardiac hypertrophy. We also investigated the mechanism of miR-100-5p on autophagy with dual-luciferase reporter assays, RNA immunoprecipitation (RIP), quantitative real-time PCR (qRT-PCR), western blot, immunofluorescence, and transmission electron microscopy (TEM). The results showed that miR-100-5p was highly expressed in hypertrophic hearts and Ang II-induced cardiomyocytes. Overexpression of miR-100-5p promoted the expression of cardiac hypertrophy markers ANP, BNP and ß-MHC and cell surface area, while those were suppressed by miR-100-5p inhibitor. Knockdown of miR-100-5p by antagomiR significantly improves cardiac function and attenuate cardiac hypertrophy in vivo. Mechanistic investigation has found that miR-100-5p promote autophagy by targeting mTOR. Inhibition of autophagy by 3-methyladenine (3-MA) or mTOR overexpression could reverse the function of miR-100-5p in cardiac hypertrophy. These results elucidate that miR-100-5p promoted the pathogenesis of cardiac hypertrophy through autophagy activation by targeting mTOR.

Weighted correlation network bioinformatics uncovers a key molecular biosignature driving the left-sided heart failure.

BACKGROUND: Left-sided heart failure (HF) is documented as a key prognostic factor in HF. However, the relative molecular mechanisms underlying left-sided HF is unknown. The purpose of this study is to unearth significant modules, pivotal genes and candidate regulatory components governing the progression of left-sided HF by bioinformatical analysis. METHODS: A total of 319 samples in GSE57345 dataset were used for weighted gene correlation network analysis (WGCNA). ClusterProfiler package in R was used to conduct functional enrichment for genes uncovered from the modules of interest. Regulatory networks of genes were built using Cytoscape while Enrichr database was used for identification of transcription factors (TFs). The MCODE plugin was used for identifying hub genes in the modules of interest and their validation was performed based on GSE1869 dataset. RESULTS: A total of six significant modules were identified. Notably, the blue module was confirmed as the most crucially associated with left-sided HF, ischemic heart disease (ISCH) and dilated cardiomyopathy (CMP). Functional enrichment conveyed that genes belonging to this module were mainly those driving the extracellular matrix-associated processes such as extracellular matrix structural constituent and collagen binding. A total of seven transcriptional factors, including Suppressor of Zeste 12 Protein Homolog (SUZ12) and nuclear factor erythroid 2 like 2 (NFE2L2), adrenergic receptor (AR), were identified as possible regulators of coexpression genes identified in the blue module. A total of three key genes (OGN, HTRA1 and MXRA5) were retained after validation of their prognostic value in left-sided HF. The results of functional enrichment confirmed that these key genes were primarily involved in response to transforming growth factor beta and extracellular matrix. CONCLUSION: We uncovered a candidate gene signature correlated with HF, ISCH and CMP in the left ventricle, which may help provide better prognosis and therapeutic decisions and in HF, ISCH and CMP patients.

Transcription factor TEAD1 is essential for vascular development by promoting vascular smooth muscle differentiation.

TEAD1 (TEA domain transcription factor 1), a transcription factor known for the functional output of Hippo signaling, is important for tumorigenesis. However, the role of TEAD1 in the development of vascular smooth muscle cell (VSMC) is unknown. To investigate cell-specific role of Tead1, we generated cardiomyocyte (CMC) and VSMC-specific Tead1 knockout mice. We found CMC/VSMC-specific deletion of Tead1 led to embryonic lethality by E14.5 in mice due to hypoplastic cardiac and vascular walls, as a result of impaired CMC and VSMC proliferation. Whole transcriptome analysis revealed that deletion of Tead1 in CMCs/VSMCs downregulated expression of muscle contractile genes and key transcription factors including Pitx2c and myocardin. In vitro studies demonstrated that PITX2c and myocardin rescued TEAD1-dependent defects in VSMC differentiation. We further identified Pitx2c as a novel transcriptional target of TEAD1, and PITX2c exhibited functional synergy with myocardin by directly interacting with myocardin, leading to augment the differentiation of VSMC. In summary, our study reveals a critical role of Tead1 in cardiovascular development in mice, but also identifies a novel regulatory mechanism, whereby Tead1 functions upstream of the genetic regulatory hierarchy for establishing smooth muscle contractile phenotype.

Regulation of TLR4 expression mediates the attenuating effect of erythropoietin on inflammation and myocardial fibrosis in rat heart.

The mechanism underlying the anti­inflammatory or antifibrotic activity of erythropoietin (EPO) in myocardial fibrosis (MF) remains elusive. In the current study, abdominal aortic constriction (AAC) was performed on rats and EPO and/or Toll­like receptor (TLR)4 were overexpressed in rat hearts through intramyocardial administration of lentivirus expressing the EPO and TLR4 genes. Hematoxylin and eosin staining and Masson's trichrome staining were performed on tissue sections from rat hearts for histopathological examination. ELISA was used to determine the levels of inflammatory mediators in serum. Gene expression levels were determined by quantitative polymerase chain reaction analysis and protein expression levels were determined by western blot analysis and immunofluorescence staining. The results indicated that EPO overexpression improved MF in rat hearts, by inhibiting the release of transforming growth factor (TGF)­ß1, tumor necrosis factor (TNF)­α, interleukin (IL)­6, IL­1ß, IL­17A, matrix metalloproteinase (MMP)­9 and MMP­2. Moreover, EPO overexpression suppressed the expression of TLR4, while promoting phosphoinositide 3­kinase (PI3K) and phosphorylated AKT serine/threonine kinase 1 (Akt) expression levels. However, the beneficial effects of EPO were attenuated by overexpression of TLR4. In addition, inhibition of PI3K/Akt signaling activity by treatment with LY294002 markedly reversed the protective effect of EPO on the AAC­induced MF. Taken together, the present study demonstrated that EPO may have a critical role against MF by activating PI3K/Akt signaling and by downregulating TLR4 expression, thereby inhibiting the release of TGF­ß1, TNF­α, IL­6, IL­1ß, IL­17A, MMP­9 and MMP­2. These findings suggest that the PI3K/Akt/TLR4 signaling pathway is associated with the anti­inflammatory effects of EPO and may play a role in attenuating AAC­induced MF.

Predictive value of exercise-induced atrial natriuretic peptide secretion for the presence of left atrial low-voltage areas in patients with persistent atrial fibrillation.

Objectives Left atrial (LA) low-voltage areas (LVAs) are a strong predictor of atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI). However, a non-invasive method for evaluating LA-LAVs has not been established yet. The objective of our study was to assess the predictive value of the plasma atrial natriuretic peptide (ANP) level for the presence of LA-LVAs in patients with persistent AF (PeAF). Methods Seventy-two PeAF patients underwent an exercise stress test preprocedurally. LA voltage maps were created after PVI. Demographic, clinical and echocardiographic data were recorded. Plasma levels of ANP at baseline (ANP0) and increase induced by exercise (ΔANP) were also measured. Results Compared with patients without LA-LVAs, patients with LA-LVAs had a longer history of AF, higher CHADS2 score and higher ANP0 and lower ΔANP. LA-LVAs extent correlated with duration of AF history, CHADS2 score and ΔANP (R = -0.76, P < 0.01). Only ΔANP independently predicted the presence of LA-LVAs (OR =1.63, P = 0.02). Derived from the ROC curve, ΔANP <55 pg/mL predicted the presence of LA-LVAs with high accuracy (AUC =0.78; 95% CI =0.57-0.87, P < 0.01). Conclusions Exercise-induced secretion of ANP may be used to predict the presence of LA-LVAs in patients with PeAF before catheter ablation.

The carboxyl terminus of heat shock protein 70-interacting protein (CHIP) participates in high glucose-induced cardiac injury.

The carboxyl terminus of heat shock protein 70-interacting protein (CHIP) is confirmed to have a protective effect on the myocardium, but its effect on diabetic cardiomyopathy is unclear. Small interfering RNA (siRNA) was used for knockdown experiments in neonatal rat cardiomyocytes to examine the function of CHIP in high glucose-induced injury. High glucose stimulated the production of reactive oxygen species (ROS), nicotinamide adenine dinucleotide phosphate oxidase (NOX), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and monocyte chemoattractant protein-1 (MCP-1) production. However, cardiomyocytes lacking CHIP suffered from increased oxidative stress and inflammatory responses. High glucose increased the expression of Bax and caspase-3 mRNAs, decreased the expression of Bcl-2 mRNA, and up-regulated the expression of the nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) proteins. However, upon CHIP knockdown, the expression of Bax and caspase-3 mRNAs increased even further, and the expression of Bcl-2 mRNA was further suppressed. The expression of the phosphorylated p65 and p38 proteins (p-p65 and p-p38) was also further enhanced. Thus, CHIP is a potent cardioprotective molecule.

Erythrocyte membrane trans-fatty acid index is positively associated with a 10-year CHD risk probability.

Industry-generated trans-fatty acids (TFA) are detrimental to risk of CHD, but ruminant-originated TFA have been reported as neutral or equivocal. Therefore, the total TFA amount should not be the only factor considered when measuring the effects of TFA. In the present study, we addressed whether a version of the TFA index that unifies the effects of different TFA isomers into one equation could be used to reflect CHD risk probability (RP). The present cross-sectional study involved 2713 individuals divided into four groups that represented different pathological severities and potential risks of CHD: acute coronary syndrome (ACS, n 581); chronic coronary artery disease (CCAD, n 631); high-risk population (HRP, n 659); healthy volunteers (HV, n 842). A 10-year CHD RP was calculated. Meanwhile, the equation of the TFA index was derived using five TFA isomers (trans-16 : 1n-7, trans-16 : 1n-9, trans-18 : 1n-7, trans-18 : 1n-9 and trans-18 : 2n-6n-9), which were detected in the whole blood, serum and erythrocyte membranes of each subject. The TFA index and the 10-year CHD RP were compared by linear models. It was shown that only in the erythrocyte membrane, the TFA isomers were significantly different between the groups. In the ACS group, industry-generated TFA (trans-16 : 1n-9, trans-18 : 1n-9 and trans-18 : 2n-6n-9) were the highest, whereas ruminant-originated TFA (trans-16 : 1n-7 and trans-18 : 1n-7), which manifested an inverse relationship with CHD, were the lowest, and vice versa in the HV group. The TFA index decreased progressively from 7·12 to 5·06, 3·11 and 1·92 in the ACS, CCAD, HRP and HV groups, respectively. The erythrocyte membrane TFA index was positively associated with the 10-year CHD RP (R 2 0·9981) and manifested a strong linear correlation, which might reflect the true pathological severity of CHD.

Therapeutic effects of neuregulin-1 gene transduction in rats with myocardial infarction.

AIM: In this study, we investigated whether lentivirus-mediated gene transduction improves the cardiac function in rats with myocardial infarction and the mechanisms involved. METHODS AND RESULTS: Briefly, lentivirus carrying human neuregulin-1 (hNRG-1) gene was injected into infarcted myocardium of rats. Four weeks later, lentivirus-mediated gene transduction promoted hNRG-1 gene and protein expression. Overexpression of hNRG-1 increased the number of microvessels in the ischemic myocardium and decreased the number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-stained positive cells. Furthermore, qRT-PCR assay showed that hNRG-1 was capable of increasing the expression of bcl-2 and VEGF-A while decreasing the expression of bax. Western blot analysis suggested that overexpression of hNRG-1 activated the PI3K/Akt pathway and increased the phosphorylation of Akt and eNOS. CONCLUSION: These findings suggest that NRG-1 gene transduction can improve cardiac function by promoting angiogenesis and preventing apoptosis.

Therapeutic effects of neuregulin-1 in diabetic cardiomyopathy rats.

BACKGROUND: Diabetic cardiomyopathy (DCM) is a disorder of the heart muscle in people with diabetes, which is characterized by both systolic and diastolic dysfunction. The effective treatment strategy for DCM has not been developed. METHODS: Rats were divided into 3 groups with different treatment. The control group was only injected with citrate buffer (n = 8). The diabetes group and diabetes treated group were injected with streptozotocin to induce diabetes. After success of diabetes induction, the rats with diabetes were treated with (diabetes treated group, n = 8) or without (diabetes group, n = 8) recombinant human Neuregulin-1 (rhNRG-1). All studies were carried out 16 weeks after induction of diabetes. Cardiac catheterization was performed to evaluate the cardiac function. Apoptotic cells were determined by TUNEL staining. Left ventricular (LV) sections were stained with Masson to investigate myocardial collagen contents. Related gene expressions were analyzed by quantitative real-time PCR (qRT-PCR). RESULTS: Diabetes impaired cardiac function manifested by reduced LV systolic pressure (LVSP), maximum rate of LV pressure rise and fall (+dp/dt max and -dp/dt max) and increased LV end-diastolic pressure (LVEDP). The rhNRG-1 treatment could significantly alleviate these symptoms and improve heart function. More TUNEL staining positive cells were observed in the diabetic group than that in the control group, and the rhNRG-1 treatment decreased apoptotic cells number. Furthermore, qRT-PCR assay demonstrated that rhNRG-1 treatment could decrease the expression of bax and caspase-3 and increase that of bcl-2. Collagen volume fraction was higher in the diabetic group than in the control group. Fibrotic and fibrotic related mRNA (type I and type III collagen) levels in the myocardium were significantly reduced by administration of rhNRG-1. CONCLUSION: rhNRG-1 could significantly improve the heart function and reverse the cardiac remodeling of DCM rats with chronic heart failure. These results support the clinical possibility of applying rhNRG-1 as an optional therapeutic strategy for DCM treatment in the future.