Project description:Primary aldosteronism is characterized by excess aldosterone secretion by the adrenal gland independent of the renin-angiotensin system and accounts for ~10% of hypertensive patients. Excess aldosterone causes cardiac hypertrophy, fibrosis, inflammation, and hypertension. The molecular mechanisms that trigger the onset and progression of aldosterone-mediated cardiac injury remain incompletely understood. MicroRNAs (miRNAs) are endogenous, small, noncoding RNAs that have been implicated in multiple cardiac pathologies; however, their regulation and role in aldosterone-mediated cardiac injury and dysfunction remains mostly unknown. We previously reported that microRNA-21 (miR-21) is the most upregulated miRNA by excess aldosterone in the left ventricle in a rat experimental model of primary aldosteronism. To elucidate the role of miR-21 in aldosterone-mediated cardiac injury and dysfunction, miR-21 knockout mice and their wild-type littermates were treated with aldosterone infusion and salt in the drinking water for 2 or 8 wk. miR-21 genetic ablation exacerbated aldosterone/salt-mediated cardiac hypertrophy and cardiomyocyte cross-sectional area. Furthermore, miR-21 genetic ablation increased the cardiac expression of fibrosis and inflammation markers and fetal gene program. miR-21 genetic ablation increased aldosterone/salt-mediated cardiac dysfunction but did not affect aldosterone/salt-mediated hypertension. miR-21 target gene Sprouty 2 may be implicated in the cardiac effects of miR-21 genetic ablation. Our study shows that miR-21 genetic ablation exacerbates aldosterone/salt-mediated cardiac hypertrophy, injury, and dysfunction blood pressure independently. These results suggest that miR-21 plays a protective role in the cardiac pathology triggered by excess aldosterone. Furthermore, miR-21 supplementation may be a novel therapeutic approach to abolish or mitigate excess aldosterone-mediated cardiovascular deleterious effects in primary aldosteronism.

Project description:Chronic endotheliitis and various cardiovascular co-morbidities are more likely to develop in patients who are recovering from a post-acute SARS-CoV-2 infection. Despite a growing body of clinical data suggesting that the endothelium could be the cause of both cardiac injury and the multi-organ damage found in COVID-19 patients, there is no clear link between endothelial (EC) dysfunction and increased cardiac risk during long COVID. Here, we studied long COVID-19-associated endotheliitis and its implications on cardiac dysfunction. Thrombotic vascular tissues from long COVID patients were harvested and profiled to identify the different mechanisms of viral-induced EC pathogenesis. Human induced pluripotent stem cell (iPSC)–derived ECs were leveraged to model endotheliitis in-a-dish after exposure to SARS-CoV-2, which showed similar EC dysfunction and upregulation of specific cytokines such as CCL2 and IL6, as seen in the primary ECs of long COVID patients. 3D fabricated cardiac organoids generated from iPSC-ECs and iPSC-derived cardiomyocytes (iPSC-CMs) were utilized to understand the pathological influence of endotheliitis on cardiac dysfunction. Notably, cardiac dysfunction was observed only in cardiac organoids that were fabricated with both iPSC-CMs and iPSC-ECs after exposure to SARS-CoV-2. Simultaneous profiling of chromatin accessibility and gene expression dynamics via integration of ATAC-seq and RNA-seq at a single cell resolution revealed CCL2 as the prime cytokine responsible for the non-endothelial “phenotype switching” and the impending cardiac dysfunction in cardiac organoids. This was further validated by high-throughput proteomics that showed CCL2 to be released only by cardiac organoids that were fabricated with iPSC-CMs and iPSC-ECs after SARS-CoV-2 infection. Lastly, disease modeling of the cardiac organoids as well as exposure of human ACE2 transgenic mice to SARS-CoV-2 spike proteins uncovered a putative mechanism for the cardiac dysfunction involving posttranslational modification of cardiac proteins driven by oxidative stress and inflammation. These results suggest that EC-released cytokines can contribute to the pathogenesis of long COVID-associated cardiac dysfunction, and thus a thorough clinical profiling of vascular health could help identify early signs of heart disease in COVID-19 patients.

Dataset Information

Role and Regulation of MicroRNAs in Aldosterone-Mediated Cardiac Injury and Dysfunction in Male Rats.

Publications

Role and Regulation of MicroRNAs in Aldosterone-Mediated Cardiac Injury and Dysfunction in Male Rats.

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