title: Urocortin 3 marks mature human primary and embryonic stem cell-derived pancreatic alpha and beta cells.
abstract: The peptide hormone Urocortin 3 (Ucn 3) is abundantly and exclusively expressed in mouse pancreatic beta cells where it regulates insulin secretion. Here we demonstrate that Ucn 3 first appears at embryonic day (E) 17.5 and, from approximately postnatal day (p) 7 and onwards throughout adult life, becomes a unifying and exclusive feature of mouse beta cells. These observations identify Ucn 3 as a potential beta cell maturation marker. To determine whether Ucn 3 is similarly restricted to beta cells in humans, we conducted comprehensive immunohistochemistry and gene expression experiments on macaque and human pancreas and sorted primary human islet cells. This revealed that Ucn 3 is not restricted to the beta cell lineage in primates, but is also expressed in alpha cells. To substantiate these findings, we analyzed human embryonic stem cell (hESC)-derived pancreatic endoderm that differentiates into mature endocrine cells upon engraftment in mice. Ucn 3 expression in hESC-derived grafts increased robustly upon differentiation into mature endocrine cells and localized to both alpha and beta cells. Collectively, these observations confirm that Ucn 3 is expressed in adult beta cells in both mouse and human and appears late in beta cell differentiation. Expression of Pdx1, Nkx6.1 and PC1/3 in hESC-derived Ucn 3(+) beta cells supports this. However, the expression of Ucn 3 in primary and hESC-derived alpha cells demonstrates that human Ucn 3 is not exclusive to the beta cell lineage but is a general marker for both the alpha and beta cell lineages. Ucn 3(+) hESC-derived alpha cells do not express Nkx6.1, Pdx1 or PC1/3 in agreement with the presence of a separate population of Ucn 3(+) alpha cells. Our study highlights important species differences in Ucn 3 expression, which have implications for its utility as a marker to identify mature beta cells in (re)programming strategies.
authors.affiliation: Peptide Biology Laboratories, The Salk Institute for Biological Studies, La Jolla, California, USA.
authors.forename: Talitha
authors.initials: T
authors.lastname: van der Meulen
authors.forename: Ruiyu
authors.initials: R
authors.lastname: Xie
authors.forename: Olivia G
authors.initials: OG
authors.lastname: Kelly
authors.forename: Wylie W
authors.initials: WW
authors.lastname: Vale
authors.forename: Maike
authors.initials: M
authors.lastname: Sander
authors.forename: Mark O
authors.initials: MO
authors.lastname: Huising
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D019070:Cell Lineage; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D015870:Gene Expression; D050416:Glucagon-Secreting Cells / Q000166:cytology / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D050417:Insulin-Secreting Cells / Q000166:cytology / Q000378:metabolism*; D007515:Islets of Langerhans / Q000166:cytology / Q000378:metabolism; D051379:Mice; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D054832:Urocortins / Q000235:genetics / Q000378:metabolism*
chemical_list: D018398:Homeodomain Proteins; D015534:Trans-Activators; D054832:Urocortins; C084010:pancreatic and duodenal homeobox 1 protein