We have previously described a procedure that allows us to efficiently differentiate cells with hepatocyte characteristics from human induced pluripotent stem cells. We have also shown that iPSCs derived from patients with inborn errors of hepatic metabolism can be used to model metabolic liver disease in culture. Here we propose to use this approach to study a rare disease called Mitochondrial DNA Depletion Syndrome 3 (Hepatocerebral type) (MTDPS3) that is caused by mutations in the Deoxyguanine Kinase (DGUOK) gene. We propose to generate iPSC-derived hepatocytes that contain different mutations in DGUOK and compare the effect of these mutations on mtDNA copy number, mitochondrial activity, and hepatocyte function. Finally, we propose to use these cells as a platform to identify drugs that can be used to treat MTDPS3 and potentially other mitochondrial DNA depletion syndromes.
We have shown previously that we can produce liver cells from human induced pluripotent stem cells (hiPSCs) and as a consequence we can use this cell culture model to unravel the complex molecular mechanisms that underlie human liver disease. Here we propose to use this system to understand a mitochondrial disease that affects liver cells called MTDPS3, which is caused by mutations in a gene called DGUOK and is normally fatal. We plan to use the system to discover drugs that can be used to treat children with MTDPS3.