Single-cell insights: pioneering an integrated atlas of chromatin accessibility and transcriptomic landscapes in diabetic cardiomyopathy.

BACKGROUND: Diabetic cardiomyopathy (DCM) poses a growing health threat, elevating heart failure risk in diabetic individuals. Understanding DCM is crucial, with fibroblasts and endothelial cells playing pivotal roles in driving myocardial fibrosis and contributing to cardiac dysfunction. Advances in Multimodal single-cell profiling, such as scRNA-seq and scATAC-seq, provide deeper insights into DCM's unique cell states and molecular landscape for targeted therapeutic interventions. METHODS: Single-cell RNA and ATAC data from 10x Multiome libraries were processed using Cell Ranger ARC v2.0.1. Gene expression and ATAC data underwent Seurat and Signac filtration. Differential gene expression and accessible chromatin regions were identified. Transcription factor activity was estimated with chromVAR, and Cis-coaccessibility networks were calculated using Cicero. Coaccessibility connections were compared to the GeneHancer database. Gene Ontology analysis, biological process scoring, cell-cell communication analysis, and gene-motif correlation was performed to reveal intricate molecular changes. Immunofluorescent staining utilized various antibodies on paraffin-embedded tissues to verify the findings. RESULTS: This study integrated scRNA-seq and scATAC-seq data obtained from hearts of WT and DCM mice, elucidating molecular changes at the single-cell level throughout the diabetic cardiomyopathy progression. Robust and accurate clustering analysis of the integrated data revealed altered cell proportions, showcasing decreased endothelial cells and macrophages, coupled with increased fibroblasts and myocardial cells in the DCM group, indicating enhanced fibrosis and endothelial damage. Chromatin accessibility analysis unveiled unique patterns in cell types, with heightened transcriptional activity in myocardial cells. Subpopulation analysis highlighted distinct changes in cardiomyocytes and fibroblasts, emphasizing pathways related to fatty acid metabolism and cardiac contraction. Fibroblast-centered communication analysis identified interactions with endothelial cells, implicating VEGF receptors. Endothelial cell subpopulations exhibited altered gene expressions, emphasizing contraction and growth-related pathways. Candidate regulators, including Tcf21, Arnt, Stat5a, and Stat5b, were identified, suggesting their pivotal roles in DCM development. Immunofluorescence staining validated marker genes of cell subpopulations, confirming PDK4, PPARγ and Tpm1 as markers for metabolic pattern-altered cardiomyocytes, activated fibroblasts and endothelial cells with compromised proliferation. CONCLUSION: Our integrated scRNA-seq and scATAC-seq analysis unveils intricate cell states and molecular alterations in diabetic cardiomyopathy. Identified cell type-specific changes, transcription factors, and marker genes offer valuable insights. The study sheds light on potential therapeutic targets for DCM.

[Effect of rosiglitazone on tumor necrosis factor-alpha-induced nuclear factor-kappaB and coupling factor 6 expressions in human umbilical vein endothelial cells].

OBJECTIVE: To investigate the effect of rosiglitazone on the expression of nuclear factor-kappaB (NF-kappaB) and coupling factor 6 (CF6) induced by tumor necrosis factor-alpha (TNF-alpha) in cultured human umbilical vein endothelial cells (HUVEC). METHODS: Cultured HUVEC of passage 3-5 were stimulated with TNF-alpha and then cultured in the presence of rosiglitazone. The expression of CF6 and NF-kappaB subunit p65 were evaluated by immunocytochemistical method. RESULTS: Pretreatment of HUVECs with rosiglitazone inhibited TNF-alpha-induced expression of CF6 in a dose-dependent manner. The activation of CF6 stimulated by TNF-alpha was suppressed by ROS in a dose-dependent manner. CONCLUSION: TNF-alpha-induced enhancement of the gene expression and release of CF6 is mediated by activation of NF-kappaB signaling pathway. ROS can inhibit the activation of IKK, block NF-kappaB signaling pathway and inhibit the expression of CF6, which may be the mechanism underlying the action of TZDs on hypertension.