Defects in low-density lipoprotein receptor (LDLR) are associated with familial hypercholesterolemia (FH), manifested by atherosclerosis and cardiovascular disease. Defective LDLR in hepatocytes leads to increased blood cholesterol level that damage vascular cells, especially endothelial cells, through oxidative stress and inflammation. However, the distinctions between endothelial cells from individuals with normal and defective LDLR are not yet fully comprehended. In this study, we obtained and examined endothelial derivatives of induced pluripotent stem cells (iPSC) generated previously from conditionally healthy donors and compound heterozygous FH patients carrying pathogenic LDLR alleles. In normal iPSC-derived endothelial cells (iPSC-EC), we detected the LDLR protein predominantly in its mature form, while iPSC-EC from patients with FH display reduced level of mature LDLR and show abolished low-density lipoprotein uptake. RNA-seq of iPSC-EC with mutant LDLR revealed a unique transcriptome profile comprising downregulated genes related to monocarboxylic acid transport, exocytosis and cell adhesion, as well as upregulated signaling pathways of cell secretion and leukocyte activation. Overall, these findings suggest that LDLR defects increases susceptibility of endothelial cells to inflammation and oxidative stress. This, combined with elevated extrinsic cholesterol levels, may result in accelerated endothelial dysfunction, contributing to early progression of atherosclerosis and other cardiovascular pathologies related to FH.
Biology and Life Sciences, Cell and Developmental Biology
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