Cell Reports
Volume 19, Issue 7, 16 May 2017, Pages 1456-1466
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Article
Lack of MTTP Activity in Pluripotent Stem Cell-Derived Hepatocytes and Cardiomyocytes Abolishes apoB Secretion and Increases Cell Stress

https://doi.org/10.1016/j.celrep.2017.04.064Get rights and content
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Highlights

  • Disease modeling of abetalipoproteinemia (ABL) using patient-specific iPSCs

  • MTTP mutation correction by CRISPR/Cas9 rescues the ABL phenotype

  • Cardiomyocytes carrying an MTTP mutation are hypersensitive to metabolic stress

Summary

Abetalipoproteinemia (ABL) is an inherited disorder of lipoprotein metabolism resulting from mutations in microsomal triglyceride transfer protein (MTTP). In addition to expression in the liver and intestine, MTTP is expressed in cardiomyocytes, and cardiomyopathy has been reported in several ABL cases. Using induced pluripotent stem cells (iPSCs) generated from an ABL patient homozygous for a missense mutation (MTTPR46G), we show that human hepatocytes and cardiomyocytes exhibit defects associated with ABL disease, including loss of apolipoprotein B (apoB) secretion and intracellular accumulation of lipids. MTTPR46G iPSC-derived cardiomyocytes failed to secrete apoB, accumulated intracellular lipids, and displayed increased cell death, suggesting intrinsic defects in lipid metabolism due to loss of MTTP function. Importantly, these phenotypes were reversed after the correction of the MTTPR46G mutation by CRISPR/Cas9 gene editing. Together, these data reveal clear cellular defects in iPSC-derived hepatocytes and cardiomyocytes lacking MTTP activity, including a cardiomyocyte-specific regulated stress response to elevated lipids.

Keywords

abetaliproteinemia
induced pluripotent stem cells
iPSC-derived hepatocytes and cardiomyocytes
lipid accumulation
apoB
cardiac stress

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These authors contributed equally

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