Abstract 3105: Lamin Mutations: Single Nuclei Multiomic Analysis Reveals Endothelial Cell Dysfunction And Its Cardiovascular Implications

Abstract

Background: LMNA-related dilated cardiomyopathy (DCM) or cardiolaminopathy is an autosomal dominant trait with complete penetrance resulting in left ventricular enlargement and cardiac dysfunction. LMNA mutations in DCM have been shown to cause to ventricular arrythmias and conduction deficits. The interplay between the LMNA gene and other cell types have yet to be fully elucidated. Notably, cardiolaminopathy patients present with prominent cardiac fibrosis, but the mechanistic link between LMNA mutations and the development of fibrosis remains inconclusive. Additionally, LMNA is expressed in the endothelium, and patients with cardiolaminopathy exhibit distinct endothelial dysfunction. Hypothesis: We hypothesize that LMNA mutations prompt a cascade of pathological alterations on the endothelium, causing vascular dysfunction and fibrosis through endothelial to mesenchymal transition (EndoMT). Aims: Next generation sequencing platforms are critical to identifying these epigenetic and transcriptomic changes in the endothelium. Combining sequencing technology with our iPSC platform, we aim to unravel the mechanism behind vascular dysfunction and fibrosis in LMNA-DCM to uncover novel therapeutic targets and treatment strategies. Methods: We performed single nuclei multiome (RNA and ATAC) on cardiac tissue from one patient with LMNA-dilated cardiomyopathy. Frozen tissues were minced into pieces before digestion. We then utilized patient-specific induced pluripotent stem cells (iPSCs) and CRISPR-generated isogenic controls. We differentiated to endothelial cells (iPSC-ECs) and nuclei capture was performed after 24hr flow. Results: Endothelial cell clusters from cardiac tissue exhibit increased stress and mesenchymal markers. Phenotypic shift and EC dysfunction was corroborated with iPSC-ECs derived from two LMNA-DCM patients. Conclusion: These results present important considerations highlighting vascular dysfunction in LMNA-DCM and notes the importance of the endothelium in cardiac health. By analyzing these datasets produced from LMNA-DCM cardiac tissue and our iPSC-EC platform, there is opportunity to both define the mechanisms that causes cardiac fibrosis and to develop new therapeutic strategies.