2050-P: A Multiomics Investigation of a Patient-Derived HNF-1A MODY IPSC Disease Model Reveals Insights into Its Role in Pancreatic Islet Development and Function

Heterozygous loss of function mutations in HNF1A, encoding the transcription factor hepatocyte nuclear factor 1 alpha (HNF-1A) are the most common cause of monogenic diabetes. HNF-1A is involved in both beta cell development and mature cell function. However, model organisms have often failed to faithfully recapitulate the human phenotypes. As such, we used a patient-derived HNF1A Pro291fsinsC iPSC model and CRISPR-Cas9 genome editing to correct the mutation and generate an isogenic control. iPSC clones (n=6) were differentiated towards the endocrine lineage in triplicate, with RNA-seq (bulk and single-cell) and ATAC-seq performed at definitive endoderm (DE), pancreatic endoderm (PE) and beta-like cells (BLC) stages. RNA-seq data confirmed HNF1A haploinsuffiency in the patient cell lines, with corrected cell lines demonstrating restored HNF1A expression at both transcript and protein level. At the BLC stage, there was a significant overlap in differentially expressed genes and HNF1A targets identified in an independent HNF1A knock-down experiment in the EndoC-βh1 cell line (p=4.4e-132). Corrected clones demonstrated a higher expression of INS (p=7.2e-03), insulin secretion genes and effects on pancreas progenitor cell genes indicating that HNF1A may mediate the cellular composition of the pancreatic islet. Bulk RNA-seq data were also supported in the preliminary analysis of the single-cell RNA-seq data. Open chromatin, assessed by ATAC-seq was significantly different between patient and corrected lines, with >90% of the sites being more accessible at both PE and BLC stages in the corrected clones. These sites were enriched for HNF1A binding motifs, implicating HNF1A in the establishment of open chromatin. In conclusion, our patient-derived HNF1A-MODY iPSC model recapitulates a number of features of HNF1A-MODY, as well as providing insights into the cellular and molecular phenotypes caused by HNF-1A deficiency. Disclosure C. Duff: Research Support; Self; Novo Nordisk A/S. R. Jensen: None. M. Perez-Alcantara: None. M. Rasmussen: None. A. Grotz: None. M. Jansen: None. B. Holst: None. C. Clausen: None. N.A.J. Krentz: None. M. Hansson: Employee; Self; Novo Nordisk A/S. M.I. McCarthy: Advisory Panel; Self; Illumina. Consultant; Self; Eli Lilly and Company, Novo Nordisk Inc., Zoe Global Ltd. Employee; Self; Genentech, Inc. Research Support; Self; AbbVie Inc., Merck & Co., Inc., Sanofi-Aventis, Servier, Takeda UK. A.L. Gloyn: Consultant; Self; Merck Sharp & Dohme Corp. Employee; Spouse/Partner; Genentech, Inc. Research Support; Self; Novo Nordisk A/S. A. Wesolowska-Andersen: None. C. Honore: Employee; Self; Novo Nordisk A/S. Stock/Shareholder; Self; Novo Nordisk A/S. Funding Innovative Medicines Initiative (115439)