GATA6 Plays an Important Role in the Induction of Human Definitive Endoderm, Development of the Pancreas, and Functionality of Pancreatic β Cells

Abstract

SummaryInduced pluripotent stem cells were created from a pancreas agenesis patient with a mutation in GATA6. Using genome-editing technology, additional stem cell lines with mutations in both GATA6 alleles were generated and demonstrated a severe block in definitive endoderm induction, which could be rescued by re-expression of several different GATA family members. Using the endodermal progenitor stem cell culture system to bypass the developmental block at the endoderm stage, cell lines with mutations in one or both GATA6 alleles could be differentiated into β-like cells but with reduced efficiency. Use of suboptimal doses of retinoic acid during pancreas specification revealed a more severe phenotype, more closely mimicking the patient’s disease. GATA6 mutant β-like cells fail to secrete insulin upon glucose stimulation and demonstrate defective insulin processing. These data show that GATA6 plays a critical role in endoderm and pancreas specification and β-like cell functionality in humans.

GATA factors in pancreas development and disease

“…[65][66][67][68] The expression of GATA4 and GATA6 in hPSC differentiation cultures has been recently reported. 69,70 Both GATA4 and GATA6 were found to be coexpressed at the definitive endoderm as well as early pancreatic progenitor stages, similar to what it is observed in mice. As pancreatic progenitor cells differentiate into ß-like cells, GATA4 and GATA6 expression decrease (particularly GATA6) with no substantial expression in mature insulinsecreting cells.…”

“…The recent development of protocols for stepwise differentiation of hESCs and induced pluripotent stem cells (hPSCs) toward β‐cells constitutes a relevant in vitro model for studying human pancreatic formation . The expression of GATA4 and GATA6 in hPSC differentiation cultures has been recently reported . Both GATA4 and GATA6 were found to be coexpressed at the definitive endoderm as well as early pancreatic progenitor stages, similar to what it is observed in mice.…”

“…The hPSCs in vitro differentiation approaches have also made it possible to directly assess the effect of GATA6 inactivation on human ß cell development. All the studies reported the generation of ß cells from both homozygous and heterozygous GATA6 ‐deficient cell lines albeit with decreased efficiency . Furthermore, hPSC‐derived ß cells carrying mutations in GATA6 displayed decreased expression of genes important for ß cell function including endocrine hormones and proteins involved in insulin secretion.…”

“…All the studies reported the generation of ß cells from both homozygous and heterozygous GATA6-deficient cell lines albeit with decreased efficiency. [69][70][71] Furthermore, hPSC-derived ß cells carrying mutations in GATA6 displayed decreased expression of genes important for ß cell function including endocrine hormones and proteins involved in insulin secretion. One of the studies also reported defects in glucosestimulated insulin secretion in GATA6-deficient ß cells, 70 although it was not observed in other studies.…”

The Use of Human Pluripotent Stem Cells for Modeling Liver Development and Disease

“…Previous investigations of GATA6 in murine models have proven difficult due to early‐stage lethality . Using loss‐of‐function experiments in human PSCs, three separate groups have shown that GATA6 is essential for definitive endoderm formation . The use of PSCs allowed for the investigation of endoderm formation in isolation, negating lethality derived from different lineages, in a human context.…”