Abstract 15443: Unexpected Role of PCSK9 in Human Pluripotent Stem Cells and Their Differentiation
Introduction: We previously showed that patient-derived induced pluripotent stem cells (hiPSCs) differentiated into hepatocytes is a relevant model to study the impact of PCSK9 gain-of-function (GOF) and loss-of-function (LOF) mutations on cholesterol metabolism regulation. The hiPSCs hepatic differentiation process reproduces the major steps of mammalian liver development. Upon PCSK9 gene expression analysis, we discovered that PCSK9 expression is tightly regulated during hiPSCs differentiation, with the highest expression level in undifferentiated hiPSCs.
Hypothesis: Undifferentiated hiPSCs and their early differentiation will provide a novel approach to highlight new PCSK9 functions.
Methods: Control hiPSCs or carrying the S127R GOF or R104C/V114A LOF mutations, and hiPSCs silenced for PCSK9 expression with the use of a shRNA, were analyzed in undifferentiated hiPSCs (gene expression and protein) and during their endoderm (hepatocytes) and mesoderm (cardiomyocytes) differentiation (gene expression). The impacts of LOF mutations and shRNA-mediated PCSK9 expression inhibition on hiSPCs proliferation were also evaluated. Finally, differential PCSK9 expression during early mouse embryonic development has been elucidated by immunofluorescent staining.
Results: We detected a differential expression of several genes of a cell signaling pathway involved in hiPSCs pluripotency and differentiation. The impact on protein effectors has been verified and we identified a new potential intracellular target of PCSK9. While we did not observe an effect during endoderm differentiation of hiPSCs, we detected an abnormal expression of the endodermal transcription factor FOXA2 during the mesoderm differentiation whenever PCSK9 activity or expressions were modified. Finally, our study showed that the R104C/V114A PCSK9 LOF mutations or PCSK9 silencing with shRNA significantly reduced hiPSCs proliferation. PCSK9 expression during early mouse development and throughout hiPSCs hepatic and cardiac differentiation will be discussed.
Conclusions: We described for the first time the expression of PCSK9 in pluripotent stem cells, and the use of patient-specific hiPSCs allowed us to highlight a new PCSK9 function in developmental processes.
Author Disclosures: S. Idriss: None. A. Caillaud: None. A. Girardeau: None. B. Champon: None. A. David: None. L. Arnaud: None. M. Pichelin: None. C. Le May: None. A. Prat: None. A. Camus: None. N.G. Seidah: None. B. Cariou: None. K. Si-Tayeb: None.
- © 2016 by American Heart Association, Inc.