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Pancreatic Differentiation of Stem Cells Reveals Pathogenesis of a Syndrome of Ketosis-Prone Diabetes

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posted on 03.08.2021, 15:49 by Diane Yang, Sanjeet Patel, Wojciech J. Szlachcic, Jolanta Chmielowiec, Diane Scaduto, Nagireddy Putluri, Arun Sreekumar, James Suliburk, Michael Metzker, Ashok Balasubramanyam, Malgorzata Borowiak
Genetic analysis of an adult patient with an unusual course of Ketosis-Prone Diabetes (KPD) and lacking islet autoantibodies demonstrated a nucleotide variant in the 5’-UTR of PDX1, a beta-cell development gene. When differentiated to the pancreatic lineage, his induced pluripotent stem cells stalled at the definitive endoderm stage. Metabolomic analysis of the cells revealed that this was associated with leucine hypersensitivity during transition from the definitive endoderm to the pancreatic progenitor stage, and RNA-sequencing showed defects in leucine-sensitive mTOR pathways contribute to the differentiation deficiency. CRISPR-Cas9 manipulation of the PDX1 variant demonstrated that it is necessary and sufficient to confer leucine sensitivity and the differentiation block, likely due to disruption of binding of the transcriptional regulator NFY to the PDX1 5’-UTR, leading to decreased PDX1 expression at the early pancreatic progenitor stage. Thus, the combination of an underlying defect in leucine catabolism characteristic of KPD with a functionally relevant heterozygous variant in a critical beta-cell gene that confers increased leucine sensitivity and inhibits endocrine cell differentiation resulted in the phenotype of late-onset beta-cell failure in this patient. We define the molecular pathogenesis of a diabetes syndrome and demonstrate the power of multi-omics analysis of patient-specific stem cells for clinical discovery.

Funding

This work was supported by funds from the Rutherford Chair in Diabetes Research (to AB); and the McNair Medical Institute Scholar’s Program, NIH P30-DK079638, Polish National Science Center (NCN) Polonez programme 15/19/P/NZ3/03452, and EU Horizon 2020 and MCSA 665778 (all to MB). The Metabolomics Core was supported by a CPRIT “Proteomic and Metabolomic Core Facility” Support Award (RP170005), NCI Cancer Center Support Grant P30CA125123, and intramural funds from the Dan L. Duncan Cancer Center.

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