HNF1A deficiency impairs β-cell fate, granule maturation and function. HNF1A deficiency impairs β-cell fate, granule maturation and function

Mutations in HNF1A cause Maturity Onset Diabetes of the Young type 3, the second most frequent form of diabetes caused by single gene mutation. We generated human pancreatic stem cell-derived endocrine cells with mutations in HNF1A and show that HNF1A deficiency impairs scβ-cell fate, insulin granule maturation and the secretion of insulin in a glucose responsive manner. Single-cell RNA sequencing reveals that HNF1A orchestrates a network of genes involved in glucose metabolism, zinc transport, calcium ion binding and hormone exocytosis. Furthermore, in both patients and stem cell-derived β-cells, HNF1A deficiency altered the stoichiometry of secreted c-peptide to insulin. Sulfonylurea, used in the treatment of these patients, restored both insulin secretion and stoichiometry. Significantly, uncoupling of c-peptide and insulin secretion as described here questions the common practice in using c-peptide as a proxy to evaluate β-cell function. We also demonstrate that correction of the HNF1A locus restores function, providing a path to cell therapy. Overall design: Human embryonic stem cells with different HNF1A genotypes (WT, KO1, KO2, R200Q homozygous) were differentiated into islet-like clusters of endocrine cells for 27-28 days in vitro. First set of 6 samples, clusters of islet-like cells were dissociated into single cells and analyzed by single cell RNA sequencing. There are two WT, two KO and two R200Q samples. Second set of 5 samples, clusters of islet-like cells were dissociated into single cells and insulin producing cells were purified by FACS sorting for INS-GFP. Cells were analyzed by bulk RNA sequencing. There are three WT and two KO.