DACT1 Involvement in the Cytoskeletal Arrangement of Cardiomyocytes in Atrial Fibrillation by Regulating Cx43

Identification of biomarkers, pathways, and potential therapeutic targets for heart failure using next-generation sequencing data and bioinformatics analysis

BACKGROUND

Heart failure (HF) is the most common cardiovascular diseases and the leading cause of cardiovascular diseases related deaths. Increasing molecular targets have been discovered for HF prognosis and therapy. However, there is still an urgent need to identify novel biomarkers. Therefore, we evaluated biomarkers that might aid the diagnosis and treatment of HF.

METHODS

We searched next-generation sequencing (NGS) dataset (GSE161472) and identified differentially expressed genes (DEGs) by comparing 47 HF samples and 37 normal control samples using limma in R package. Gene ontology (GO) and pathway enrichment analyses of the DEGs were performed using the g: Profiler database. The protein-protein interaction (PPI) network was plotted with Human Integrated Protein-Protein Interaction rEference (HiPPIE) and visualized using Cytoscape. Module analysis of the PPI network was done using PEWCC1. Then, miRNA-hub gene regulatory network and TF-hub gene regulatory network were constructed by Cytoscape software. Finally, we performed receiver operating characteristic (ROC) curve analysis to predict the diagnostic effectiveness of the hub genes.

RESULTS

A total of 930 DEGs, 464 upregulated genes and 466 downregulated genes, were identified in HF. GO and REACTOME pathway enrichment results showed that DEGs mainly enriched in localization, small molecule metabolic process, SARS-CoV infections, and the citric acid tricarboxylic acid (TCA) cycle and respiratory electron transport. After combining the results of the PPI network miRNA-hub gene regulatory network and TF-hub gene regulatory network, 10 hub genes were selected, including heat shock protein 90 alpha family class A member 1 (HSP90AA1), arrestin beta 2 (ARRB2), myosin heavy chain 9 (MYH9), heat shock protein 90 alpha family class B member 1 (HSP90AB1), filamin A (FLNA), epidermal growth factor receptor (EGFR), phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1), cullin 4A (CUL4A), YEATS domain containing 4 (YEATS4), and lysine acetyltransferase 2B (KAT2B).

CONCLUSIONS

This discovery-driven study might be useful to provide a novel insight into the diagnosis and treatment of HF. However, more experiments are needed in the future to investigate the functional roles of these genes in HF.

The Role of DACT Family Members in Tumorigenesis and Tumor Progression

Disheveled-associated antagonist of β-catenin (DACT), which ubiquitously expressed in human tissue, is critical for regulating cell proliferation and several developmental processes in different cellular contexts. In addition, DACT is essential for some other cellular processes, such as cell apoptosis, migration and differentiation. Given the importance of DACT in these cellular processes, many scientists are gradually interested in studying the role of DACT in tumorigenesis and cancer progression. This review article focuses on the latest research regarding the essential functions and potential DACT mechanisms in the occurrence and progression of tumors. Our study indicates that DACT may act as a tumor biomarker for cancer diagnosis and prognosis, as well as a promising therapeutic target in cancers.

Honokiol Provides Cardioprotection from Myocardial Ischemia/Reperfusion Injury (MI/RI) by Inhibiting Mitochondrial Apoptosis via the PI3K/AKT Signaling Pathway

Background

Myocardial injury refers to a major complication that occurs in myocardial ischemia/reperfusion injury (MI/RI). Honokiol is a well-recognized active compound extracted from the traditional Chinese herb known as Magnolia officinalis and is utilized in treating different vascular diseases. This research is aimed at examining whether Honokiol might alleviate myocardial injury in an MI/RI model.

Methods

Seventy-eight male C57BL/6 mice were categorized randomly into three cohorts including the Sham operation (Sham) cohort, the MI/RI cohort (Con), and the Honokiol cohort (n = 26 for each cohort). The mice in the Honokiol cohort were treated with Honokiol before MI/RI surgery (0.2 mg/kg/day for 14 days, intraperitoneal), while the mice in the Con cohort were given an intraperitoneal injection with an equivalent volume of vehicle (DMSO) daily in 14 days prior to exposure to MI/RI. After the surgery, creatine kinase- (CK-) MB and cardiac troponin T (cTnT) levels, as well as the infarct area, were measured to assess the degree of myocardial damage. Apoptotic levels were detected using terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining. Electron microscopy was utilized to identify mitochondrial damage. Lastly, the expression levels of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), cleaved caspase-9, cytochrome C (Cyt-C), B cell lymphoma/leukemia-2 (Bcl-2), B cell lymphoma/leukemia-2 associated X (Bax), AKT, p-AKT, PI3K, and p-PI3K were analyzed utilizing western blotting.

Results

Honokiol can reduce the MI/RI-induced cTnT and CK-MB levels, apoptosis index, and mitochondrial swelling in cardiomyocytes via activating the PI3K/AKT signaling pathway.

Conclusion

Honokiol provides cardiac protection from MI/RI by suppressing mitochondrial apoptosis through the PI3K/AKT signaling pathway.

Dact1 is expressed during chicken and mouse skeletal myogenesis and modulated in human muscle diseases

Vertebrate skeletal muscle development and repair relies on the precise control of Wnt signaling. Dact1 (Dapper/Frodo) is an important modulator of Wnt signaling, interacting with key components of the various Wnt transduction pathways. Here, we characterized Dact1 mRNA and protein expression in chicken and mouse fetal muscles in vivo and during the differentiation of chick primary and mouse C2C12 myoblasts in vitro. We also performed in silico analysis to investigate Dact1 gene expression in human myopathies, and evaluated the Dact1 protein structure to seek an explanation for the accumulation of Dact1 protein aggregates in the nuclei of myogenic cells. Our results show for the first time that in both chicken and mouse, Dact1 is expressed during myogenesis, with a strong upregulation as cells engage in terminal differentiation, cell cycle withdrawal and cell fusion. In humans, Dact1 expression was found to be altered in specific muscle pathologies, including muscular dystrophies. Our bioinformatic analyses of Dact1 proteins revealed long intrinsically disordered regions, which may underpin the ability of Dact1 to interact with its many partners in the various Wnt pathways. In addition, we found that Dact1 has strong propensity for liquid-liquid phase separation, a feature that explains its ability to form nuclear aggregates and points to a possible role as a molecular 'on'-'off' switch. Taken together, our data suggest Dact1 as a candidate, multi-faceted regulator of amniote myogenesis with a possible pathophysiological role in human muscular diseases.

Melatonin ameliorates myocardial injury by reducing apoptosis and autophagy of cardiomyocytes in a rat cardiopulmonary bypass model

Background

Myocardial injury is a frequent complication after cardiac surgery with cardiopulmonary bypass (CPB). This study aimed to test the hypothesis that melatonin could attenuate myocardial injury in a rat CPB model.

Methods

Eighteen male Sprague-Dawley rats were randomly divided into three groups, n = 6 for each group: the sham operation (SO) group, CPB group and melatonin group. Rats in the SO group underwent cannulation without CPB, rats in CPB group intraperitoneal injected an equal volume of vehicle daily for 7 days before being subjected to CPB and rats in melatonin group intraperitoneal injected 20 mg/kg of melatonin solution daily for 7 days before being subjected to CPB. After 120 min for CPB, the expression levels of plasma interleukin (IL) -6, IL-1β, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), malondialdehyde (MDA), creatine kinase (CK) -MB and cardiac troponin T (cTnT) were measured. Reactive oxygen species (ROS) were detected by dihydroethidium (DHE). Apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining. Mitochondrial damage and autophagosomes were detected by electron microscopy. Apoptosis inducing factor (AIF) was detected by immunofluorescence. The expression of B cell lymphoma/leukemia2 associated X (Bax), B cell lymphoma/leukemia 2 (Bcl-2), cytochrome C (Cyto-C), cleaved caspase-9, AKT, p-AKT, signal transducer and activator of transcription 3 (STAT3), p-STAT3, LC3, P62, mechanistic target of rapamycin kinase (mTOR), p-mTOR and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were determined using western blotting.

Results

Melatonin significantly decreased the levels of IL-1β, IL-6, MDA, CK-MB and cTnT and increased the levels of SOD and GSH-Px, all of which were altered by CPB. Melatonin reduced cardiomyocyte superoxide production, the apoptosis index and autophagy in cardiomyocytes induced by CPB. The AKT, STAT3 and mTOR signaling pathways were activated by melatonin during CPB.

Conclusion

Melatonin may serve as a cardioprotective factor in CPB by inhibiting oxidative damage, apoptosis and autophagy. The AKT, STAT3 and mTOR signaling pathways were involved in this process.

Multiomics Analysis of Genetics and Epigenetics Reveals Pathogenesis and Therapeutic Targets for Atrial Fibrillation

Objective

This study is aimed at understanding the molecular mechanisms and exploring potential therapeutic targets for atrial fibrillation (AF) by multiomics analysis.

Methods

Transcriptomics and methylation data of AF patients were retrieved from the Gene Expression Omnibus (GEO). Differentially expressed genes (DEGs) and differentially methylated sites between AF and normal samples were screened. Then, highly expressed and hypomethylated and lowly expressed and hypermethylated genes were identified for AF. Weighted gene coexpression network analysis (WGCNA) was presented to construct AF-related coexpression networks. 52 AF blood samples were used for whole exome sequence. The mutation was visualized by the maftools package in R. Key genes were validated in AF using independent datasets.

Results

DEGs were identified between AF and controls, which were enriched in neutrophil activation and regulation of actin cytoskeleton. RHOA, CCR2, CASP8, and SYNPO2L exhibited abnormal expression and methylation, which have been confirmed to be related to AF. PCDHA family genes had high methylation and low expression in AF. We constructed two AF-related coexpression modules. Single-nucleotide polymorphism (SNP) was the most common mutation type in AF, especially T > C. MUC4 was the most frequent mutation gene, followed by PHLDA1, AHNAK2, and MAML3. There was no statistical difference in expression of AHNAK2 and MAML3, for AF. PHLDA1 and MUC4 were confirmed to be abnormally expressed in AF.

Conclusion

Our findings identified DEGs related to DNA methylation and mutation for AF, which may offer possible therapeutic targets and a new insight into the pathogenesis of AF from a multiomics perspective.

Does Decreased SNX10 Serve as a Novel Risk Factor in Atrial Fibrillation of the Valvular Heart Disease? - A Case-Control Study

Introduction

Atrial fibrillation (AF) is the most common sustained arrhythmia. Sorting nexin 10 (SNX10) has been reported to be an important regulator in embryonic development and human diseases, however, little is known about its role in cardiac disease. The aim of this study was to investigate the clinical significance of SNX10 expression in AF.

Methods

Nineteen valvular heart disease patients with AF and nine valvular heart disease patients with sinus rhythm (SR) were enrolled. Atrial tissue samples from patients undergoing open heart surgery were examined. Atrial tissues of normal hearts were obtained from two cases’ autopsies. The SNX10 expression and its associations with the degree of fibrosis were analyzed by immunohistochemistry and Masson’s trichrome staining.

Results

SNX10 expression was detected in the cytoplasm of cardiac cells in human myocardial tissue. The SNX10 expression level was higher in the SR group than in the AF group (P=0.023). SNX10 expression was negatively associated with the degree of fibrosis (P=0.017, Spearman rho=-0.447), the New York Heart Association degree (P=0.003, Spearman rho=-0.545), left atrial diameter (P=0.038, Spearman rho=-0.393), right atrial diameter (P=0.043, Spearman rho=-0.386), and the brain natriuretic peptide (BNP) level 24 hours after surgery (P=0.030, Spearman rho=-0.426), but not the BNP level before surgery and 72 hours after surgery. No statistical significance was observed between SNX10 and the level of troponin T and C-reactive protein.

Conclusion

Decreased SNX10 might serve as a potential risk factor in AF of the valvular heart disease.

DACT2 regulates structural and electrical atrial remodeling in atrial fibrillation

Background

Atrial fibrillation (AF) is the most common sustained arrhythmia. DACT2 is a novel and important mediator of signaling pathways. The aim of this study was to investigate the clinical significance and functions of DACT2 expression in AF.

Methods

Immunohistochemistry was used to detect the DACT2 expression pattern in valvular disease patients. DACT2 was overexpressed in HL-1 cells and primary atrial fibroblasts. The expression levels of the potassium channel, the L-type calcium current channel, sodium ion channel proteins and collagen proteins were detected by real-time polymerase chain reaction (RT-PCR). The proteins involved in the Wnt and TGF-β signaling pathways were detected after DACT2 overexpression by western blotting.

Results

DACT2 expression was significantly associated with AF (P=0.016). The fibrosis ratio in the strong DACT2 expression group was significantly lower than that in the weak DACT2 expression group (weak: 0.198±0.091, strong: 0.129±0.064, P=0.048), and a negative correlation between DACT2 expression levels and fibrosis severity was observed (Spearman rho =−0.476, P=0.010). DACT2 significantly increased the expression levels of KCNE5 and decreased the levels of KCNH2 and SCN5A. Overexpression of DACT2 significantly inhibited the expression of collagen I and collagen III in primary rat atrial fibroblasts. DACT2 could facilitate β-catenin accumulation by reducing its phosphorylation at Thr41/Ser45 in HL-1 cells and inhibit the TGF-β signaling pathway in primary atrial fibroblasts.

Conclusions

DACT2 played a role in AF by regulating both structural and electrical atrial remodeling and by affecting β-catenin accumulation and TGF-β signaling, and it could serve as a protective factor against AF in valvular heart disease.