Imprinted cell memory in glycogen storage disorder 1a

Abstract

SummaryGlycogen storage disorder type 1a (GSD1a) is caused by loss-of-function mutations in the catalytic subunit of glucose-6-phosphatase enzyme (G6PC1) in the liver, kidney and intestine exclusively. Here we show the surprising results that while not expressingG6PC1, primary skin fibroblasts isolated from GSD1a patients’ skin biopsies preserve a distinctive disease phenotype irrespective of the different culture conditions under which they grow. This discovery was initially made by phenotypic image-based high content analysis (HCA). Deeper analysis into this disease phenotype, revealed impaired lysosomal and mitochondrial functions in GSD1a cells, which were driven by a transcriptional dysregulation of the NAD+/NADH-Sirt1-TFEB regulatory axis. This dysregulation impacts the normal balance between mitochondrial biogenesis and mitophagy in the patients’ cells. The distinctive GSD1a fibroblasts phenotype involves elevated H3 K27 histone acetylation and global DNA hypomethylation suggesting that in some way the disease imprinted a distinctive cell phenotype in these cells. Remarkably, GHF201, an established glycogen reducing molecule, which ameliorated GSD1a pathology in a liver-targeted inducibleL.G6pc-/-knockout mouse model, also reversed impaired cellular functions in GSD1a patients’ fibroblasts. Altogether, this experimental evidence strongly suggests that these cells express a strong and reversible disease phenotype without expressing the causalG6PC1gene.