Project description:Obesity is linked to an increased risk of atrial fibrillation (AF) via increased oxidative stress. While NADPH oxidase II (NOX2), a major source of oxidative stress and reactive oxygen species (ROS) in the heart predisposes to AF, the underlying mechanisms remain unclear. Here, we studied NOX2-mediated ROS production in obesity-mediated AF using Nox2-knock-out (KO) mice and mature human induced pluripotent stem cell-derived atrial cardiomyocytes (hiPSC-aCMs). Diet-induced obesity (DIO) mice and hiPSC-aCMs treated with palmitic acid (PA) were infused with a NOX blocker (apocynin) and a NOX2-specific inhibitor, respectively. We showed that NOX2 inhibition normalized atrial action potential duration and abrogated obesity-mediated ion channel remodeling with reduced AF burden. Unbiased transcriptomics analysis revealed that NOX2 mediates atrial remodeling in obesity-mediated AF in DIO mice, PA-treated hiPSC-aCMs, and human atrial tissue from obese individuals by upregulation of paired-like homeodomain transcription factor 2 (PITX2). Furthermore, hiPSC-aCMs treated with hydrogen peroxide, a NOX2 surrogate, displayed increased PITX2 expression, establishing a mechanistic link between increased NOX2-mediated ROS production and modulation of PITX2. Our findings offer insights into possible mechanisms through which obesity triggers AF and support NOX2 inhibition as a potential novel prophylactic or adjunctive therapy for patients with obesity-mediated AF.
Project description:Atrial fibrillation is associated with stuctural remodelling of the atria that involves various cell types, including cardiac myocytes, endothelial cells, and immune cells. Atrial myopathy forms the substrate for an increased risk for AF onset and on the other hand AF drives atrial myopathy. Atrial myopathy is linked to risk factors such as aging, hypertension, obesity, or heart failure. Aldosterone and the mineralocorticoid receptor are drivers of pathological remodeling in atrial myopathy. In this study, we investigated the effect of aldosterone on left atrial gene expression and cell-cell communication.
Project description:Single-cell RNA sequencing was performed on atrial cells isolated from mice fed either normal diet (ND) or high-fat diet (HFD) for 2 or 4 months to investigate immune and stromal remodeling during obesity-associated atrial cardiomyopathy. Distinct Lyve1+ resident and CCR2+ monocyte-derived macrophage populations were identified in obese mouse atria and were associated with atrial adiposity, fibro-fatty remodeling, and atrial fibrillation progression.
Project description:Project description: Proteomics study of the role of nucleotide oligomerization domain type 1 (NOD1) in a mouse model of heart failure. A high-throughput quantitative proteomic analysis was performed in atrial myocardium obtained from Wt- and Nod1-/--Tac mice and their respective Sham groups.
Project description:We conducted RNAseq on old PKCε KO vs old WT mouse atrial samples to identify pathways contributing to reduced inducibility and duration of AF in the old KO compared to old WT mice.
Project description:We generated mouse heart organoids from mouse embryonic stem cells. The heart organoids showed both atrium-like and ventricle-like morphology similar to those of embryonic hearts. Therefore we performed RNA-seq analysis to compare atrial and ventricular gene expression profiles between mouse embryonic hearts and induced heart organoids.
