245 - Impact of PCSK9 on human-iPSC derived cardiomyocyte mitochondrial function and metabolism (ID 1286)
Abstract
Background and Aims
Proprotein convertase subtilisin/kexin type 9 (PCSK9) is secreted into the circulation by the liver and can interact with several receptors of the LDL-R family and also with CD36 thus favoring their degradation. An increased expression of receptors of the LDL-R family in cardiomyocyte was shown to favor lipid accumulation, and dysfunction.This project is aimed at testing the hypothesis that PCSK9 might regulate lipoprotein and fatty acid metabolism via controlling lipoprotein receptors in the heart, thus modulating cardiomyocyte metabolism.
Methods
Cardiomyocyte have been differentiated from human-iPSC and after 30 days of culture have been pretreated for 24h with PCSK9 (2ng/ml) and then treated with LPDS(10%), VLDL(50µg/ml) and LDL(100µg/ml). After the incubation cells have been used for FACS analysis, real time, western blot and mass spectrometry.
Results
Gene expression analysis was performed to assess the maturation of cardiomyocyte, differentiated for 30 and 60 days from iPSC. After 30 days of differentiation, cells presented increased expression of Troponin T and genes involved in fatty acid metabolism (CD36, CPT1b, PPARg). Incubation of iPSC-CM with VLDL reduced the expression of mitochondrial fusion protein (MFN1) while mitochondrial fission (DRP1) protein were increased. This profile was associated with increased accumulation of neutral lipids and a decreased mitochondrial mass compared to control. Of note preincubation with PCSK9 reverted the phenotype.
Conclusions
Our data suggest that incubation with VLDL resulted in lipid accumulation and reduced mitochondrial mass in cardiomyocytes. Moreover, PCSK9 might limit cell lipotoxicity and reduce mitochondrial mass loss by reducing lipid receptors expression.
