The Role of ARX in Human Pancreatic Endocrine Specification

• Published in: PloS one Vol. 10; no. 12; p. e0144100
• Main Authors: Gage, Blair K, Asadi, Ali, Baker, Robert K, Webber, Travis D, Wang, Rennian, Itoh, Masayuki, Hayashi, Masaharu, Miyata, Rie, Akashi, Takumi, Kieffer, Timothy J
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 03.12.2015; Public Library of Science (PLoS)
• Subjects: Cell differentiation; Cell Differentiation - genetics; Cell division; Cell Line; Cell Lineage - physiology; Diabetes; Differentiation; Embryo cells; Embryogenesis; Embryonic stem cells; Fetuses; Genes; Genetic aspects; Genitalia; Ghrelin; Glucagon; Glucagon - genetics; Glucagon - metabolism; Homeobox; Homeodomain Proteins - genetics; Homeodomain Proteins - metabolism; Humans; Insulin; Insulin - genetics; Insulin - metabolism; Iroquois protein; Islet-1 protein; Islets of Langerhans - cytology; Islets of Langerhans - metabolism; Lissencephaly; Medical research; Mutation; Nkx2.2 protein; Paired Box Transcription Factors - genetics; Paired Box Transcription Factors - metabolism; Pancreas; Pancreatic Polypeptide - genetics; Pancreatic Polypeptide - metabolism; Pax6 protein; Physiological aspects; Physiology; Rodents; Somatostatin; Somatostatin - genetics; Somatostatin - metabolism; Specifications; Stem cells; Transcription factors; Transcription Factors - genetics; Transcription Factors - metabolism; Canada
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0144100

The in vitro differentiation of human embryonic stem cells (hESCs) offers a model system to explore human development. Humans with mutations in the transcription factor Aristaless Related Homeobox (ARX) often suffer from the syndrome X-linked lissencephaly with ambiguous genitalia (XLAG), affecting many cell types including those of the pancreas. Indeed, XLAG pancreatic islets lack glucagon and pancreatic polypeptide-positive cells but retain somatostatin, insulin, and ghrelin-positive cells. To further examine the role of ARX in human pancreatic endocrine development, we utilized genomic editing in hESCs to generate deletions in ARX. ARX knockout hESCs retained pancreatic differentiation capacity and ARX knockout endocrine cells were biased toward somatostatin-positive cells (94% of endocrine cells) with reduced pancreatic polypeptide (rarely detected), glucagon (90% reduced) and insulin-positive (65% reduced) lineages. ARX knockout somatostatin-positive cells shared expression patterns with human fetal and adult δ-cells. Differentiated ARX knockout cells upregulated PAX4, NKX2.2, ISL1, HHEX, PCSK1, PCSK2 expression while downregulating PAX6 and IRX2. Re-expression of ARX in ARX knockout pancreatic progenitors reduced HHEX and increased PAX6 and insulin expression following differentiation. Taken together these data suggest that ARX plays a key role in pancreatic endocrine fate specification of pancreatic polypeptide, somatostatin, glucagon and insulin positive cells from hESCs.