Abstract 15289: Urine Sample-derived Human Induced Pluripotent Stem Cells as a Model to Study PCSK9-mediated Autosomal Dominant Hypercholesterolemia
Introduction: Human induced pluripotent stem cells (hiPSC) are becoming a relevant model for the study of liver metabolic diseases once differentiated into hepatocyte-like cells (HLC), and it has been shown that they can faithfully recapitulate autosomal dominant hypercholesterolemia (ADH). PCSK9 is a critical modulator of cholesterol homeostasis, and quickly became a hot target for ADH pharmacological treatment strategies. However, current cellular models to further decipher the role of PCSK9 in ADH are limited, especially to study the PCSK9 gain of function mutation S127R, which seems to interfere with LDL cholesterol homeostasis intracellularly by still unknown mechanisms.
Hypothesis: Human iPS cells will provide an appropriate tool to model PCSK9-mediated ADH and screen molecules with pharmacological properties.
Methods: We used urine samples as a source of somatic cells in order to obtain hiPSC upon episomal vectors-mediated reprogramming (UhiPSC). After characterization and validation, UhiPS control or carrying the S127R mutation were differentiated into HLC.
Results: Compared to control cells, HLC-S127R secreted less PCSK9 in the media (-38.5 ± 47.2%; p=0.08), and had a 3.5 fold (±0.17; p<0.05) decrease of dil-LDL uptake. Pravastatin treatments (10μM for 24h) significantly enhanced LDL receptor (LDLR) and PCSK9 gene expression and PCSK9 secretion in both control and S127R HLC. Finally, pravastatin treatments induced a 3.2 fold (±0.84; p<0.05) increase of dil-LDL uptake in HLC-S127R compared to only a 1.3 fold (±0.09; p<0,05) increase in control HLC. This in vitro induction of HLC-S127R LDLR activity correlated with the good response of patients to statin treatment.
Conclusions: Our study demonstrates that not only patient’s urine samples provide an attractive source of somatic cells for reprogramming and hepatocyte differentiation but also a powerful tool to further study PCSK9 functions and test new therapeutic approaches.
Author Disclosures: K. Si-Tayeb: None. S. Idriss: None. B. Champon: None. A. Caillaud: None. M. Pichelin: None. L. Arnaud: None. B. Cariou: None.
- © 2014 by American Heart Association, Inc.