Identification of a LIF-responsive replication-competent human ß cell

The beta (ß) cell mass formed during embryogenesis is amplified by cell replication that occurs primarily during fetal and early postnatal development. Thereafter, ß cells become functionally mature and their mass is maintained by a very low rate of replication. For those few ß cells that replicate in adult life, it is not known how replication is initiated, uncoupled from ß cell function nor whether this occurs in a specialized subset of ß cells. To explore these issues with the aim of controlling replication of mature human ß cells, we capitalized on a YAP overexpression system that induces cell cycle re-entry in stem cell derived-ß cells. Singe cell RNA sequencing revealed an upregulation of components of the leukemia inhibitory factor (LIF) pathway upon cell cycle re-entry. Experimental activation of the LIF pathway induces replication and expansion of human stem cell derived- and adult ß cells in vitro and in vivo. In both stem cell derived- and adult human ß cells, the expression of the LIF receptor LIFR is restricted to a subset of ß cells with distinct transcriptional profiles and defines a subpopulation of ß cells with increased replication rates. Further analysis identified 15 transcription factors whose gene networks are active in replicating ß cells. Overall, this study sheds light on regulatory networks that control ß cell replication and reveals a heterogeneity in LIF responsiveness and replication competence. Overall design: Single cell analysis of LacZ- and YAPS6A-overexpressing beta cells using the 10X genomics platform and bulk RNA-seq analysis of LIFR+ and LIFR- sorted beta cells.