A novel mutation in human EMD gene and mitochondrial dysfunction in emerin knockdown cardiomyocytes.

Emerin is an inner nuclear envelope protein encoded by the EMD gene, mutations in which cause Emery-Dreifuss muscular dystrophy type 1 (EDMD1). Cardiac involvement has become a major threat to patients with EDMD1; however, the cardiovascular phenotype spectrums of emerinopathy and the mechanisms by which emerin regulates cardiac pathophysiology remain unclear. Here, we identified a novel nonsense mutation (c.C57G, p.Y19X) in the EMD gene in a Han Chinese family through high-throughput sequencing. Two family members were found to have EDMD1 with muscle weakness and cardiac arrhythmia. Mechanistically, we first discovered that knockdown of emerin in HL-1 or H9C2 cardiomyocytes lead to impaired mitochondrial oxidative phosphorylation capacity with downregulation of electron transport chain complex I and IV and upregulation of complex III and V. Moreover, loss of emerin in HL-1 cells resulted in collapsed mitochondrial membrane potential, altered mitochondrial networks and downregulated multiple factors in RNA and protein level, such as PGC1α, DRP1, MFF, MFN2, which are involved in regulation of mitochondrial biogenesis, fission and fusion. Our findings suggest that targeting mitochondrial bioenergetics might be an effective strategy against cardiac disorders caused by EMD mutations.

Identification and Verification of Feature Biomarkers Associated With Immune Cells in Dilated Cardiomyopathy by Bioinformatics Analysis.

Objective: To explore immune-related feature genes in patients with dilated cardiomyopathy (DCM). Methods: Expression profiles from three datasets (GSE1145, GSE21610 and GSE21819) of human cardiac tissues of DCM and healthy controls were downloaded from the GEO database. After data preprocessing, differentially expressed genes (DEGs) were identified by the 'limma' package in R software. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were then performed to identify biological functions of the DEGs. The compositional patterns of stromal and immune cells were estimated using xCell. Hub genes and functional modules were identified based on protein-protein interaction (PPI) network analysis by STRING webtool and Cytoscape application. Correlation analysis was performed between immune cell subtypes and hub genes. Hub genes with |correlation coefficient| > 0.5 and p value <0.05 were selected as feature biomarkers. A logistic regression model was constructed based on the selected biomarkers and validated in datasets GSE5406 and GSE57338. Results: A total of 1,005 DEGs were identified. Functional enrichment analyses indicated that extracellular matrix remodeling and immune and inflammation disorder played important roles in the pathogenesis of DCM. Immune cells, including CD8+ T-cells, macrophages M1 and Th1 cells, were proved to be significantly changed in DCM patients by immune cell infiltration analysis. In the PPI network analysis, STAT3, IL6, CCL2, PIK3R1, ESR1, CCL5, IL17A, TLR2, BUB1B and MYC were identified as hub genes, among which CCL2, CCL5 and TLR2 were further screened as feature biomarkers by using hub genes and immune cells correlation analysis. A diagnosis model was successfully constructed by using the three biomarkers with area under the curve (AUC) scores 0.981, 0.867 and 0.946 in merged dataset, GSE5406 and GSE57338, respectively. Conclusion: The present study identified three immune-related genes as diagnostic biomarkers for DCM, providing a novel perspective of immune and inflammatory response for the exploration of DCM molecular mechanisms.

Plasma protein profiling analysis in patients with atrial fibrillation before and after three different ablation techniques.

Background: There are controversies on the pathophysiological alteration in patients with atrial fibrillation (AF) undergoing pulmonary vein isolation using different energy sources. Objectives: We evaluated the changes in plasma proteins in acute phase post-ablation in patients receiving cryoballoon ablation, radiofrequency balloon ablation, or radiofrequency ablation. Methods: Blood samples from eight healthy controls and 24 patients with AF were taken on the day of admission, day 1, and day 2 post-ablation and analyzed by the Olink proximity extension assay. Proteins were identified and performed with enrichment analysis. Protein-protein interaction network and module analysis were conducted using Cytoscape software. Results: Of 181 proteins, 42 proteins in the cryoballoon group, 46 proteins in the radiofrequency balloon group, and 43 proteins in the radiofrequency group significantly changed after ablation. Most of the proteins altered significantly on the first day after ablation. Altered proteins were mainly involved in cytokine-cytokine receptor interaction. Both balloon-based ablations showed a similar shift toward enhancing cell communication and regulation of signaling while inhibiting neutrophil chemotaxis. However, radiofrequency ablation presented a different trend. Seed proteins, including osteopontin, interleukin-6, interleukin-10, C-C motif ligand 8, and matrix metalloproteinase-1, were identified. More significant proteins associated with hemorrhage and coagulation were selected in balloon-based ablations by machine learning. Conclusion: Plasma protein response after three different ablations in patients with AF mainly occurred on the first day. Radiofrequency balloon ablation shared similar alteration in protein profile as cryoballoon ablation compared with radiofrequency ablation, suggesting that lesion size rather than energy source is the determinant in pathophysiological responses to the ablation.

Outcome of non-vitamin K oral anticoagulants in the treatment of left atrial/left atrial appendage thrombus in patients with nonvalvular atrial fibrillation.

BACKGROUND: Data comparing dabigatran with rivaroxaban regarding the resolution of left atrial/left atrial appendage (LA/LAA) thrombus in patients with nonvalvular atrial fibrillation (AF) are scarce. This study aimed to compare the efficacy and safety of dabigatran vs rivaroxaban regarding the resolution of LA/LAA thrombus in patients with nonvalvular AF. METHODS: This retrospective study enrolled nonvalvular AF patients scheduled to undergo catheter ablation or cardioversion in Shanghai Ruijin Hospital between January 2014 and January 2019. Altogether, 34 patients with LA/LAA thrombus detected by transesophageal echocardiography (TEE) were enrolled. Among them, 12 patients were treated with dabigatran 150 mg bid and the other 22 with rivaroxaban 20 mg qd. Follow-up TEE was performed within greater than or equal to 3 weeks to less than 6 months of the initial TEE to evaluate the resolution of the LA/LAA thrombus. RESULTS: Baseline patient characteristics were similar in the two groups. Overall, 18 patients (81.8%) in the rivaroxaban group had complete thrombus resolution after 70.3 ± 22.1 treatment days, and 10 patients (83.3%) in the dabigatran group had complete thrombus resolution after 69.3 ± 47.9 treatment days. There was no significant difference between the groups (P = .6). TEE showed that the average length, width, and area of thrombus significantly decreased in both groups after treatment, although there was no significant difference in the amount of change in these parameters between the two groups after treatment (P = .6). Undissolved thrombus in two patients in the rivaroxaban group did dissolve after switching to dabigatran. CONCLUSIONS: The results suggest that both dabigatran and rivaroxaban are potential options for treating LA/LAA thrombus in patients with nonvalvular AF. Dabigatran could be an alternative option for the resolution of LA/LAA thrombus resistant to rivaroxaban.