Islet architecture in adult mice is actively maintained by Robo2 expression in cells

A fundamental question in developmental biology is whether tissue architectures formed during development are set for life, or require continuous maintenance signals, and if so, what are those signals. The islets of Langerhans in the pancreas can serve as an elegant model tissue to answer these questions. Islets have a nonrandom spatial architecture, which is important to proper glucose homeostasis. Islet architecture forms during embryonic development, in a morphogenesis process during development and remains passive in adulthood, or whether it requires active maintenance throughout life, has not been determined. Here we conditionally deleted Robo2 in beta cells of adult mice and observed their islet architecture following a two-month chase. We show that deleting Robo2 in adult beta cells causes significant loss of islet architecture without affecting beta cell identity, maturation, or stress, indicating that Robo2 plays a role in actively maintaining adult islet architecture. Understanding the factors required to maintain islet architecture, and thus optimize islet function, is important for developing future diabetes therapies.