Beta cell replication is the primary mechanism for maintaining postnatal beta cell mass.
The endocrine pancreas undergoes major remodeling during neonatal development when replication of differentiated beta cells is the major mechanism by which beta cell mass is regulated. The molecular mechanisms that govern the replication of terminally differentiated beta cells are unclear. We show that during neonatal development, cyclin D2 expression in the endocrine pancreas coincides with the replication of endocrine cells and a massive increase in islet mass. Using cyclin D2-/- mice, we demonstrate that cyclin D2 is required for the replication of endocrine cells but is expendable for exocrine and ductal cell replication. As a result, 14-day-old cyclin D2-/- mice display dramatically smaller islets and a 4-fold reduction in beta cell mass in comparison to their WT littermates. Consistent with these morphological findings, the cyclin D2-/- mice are glucose intolerant. These results suggest that cyclin D2 plays a key role in regulating the transition of beta cells from quiescence to replication and may provide a target for the development of therapeutic strategies to induce expansion and/or regeneration of beta cells.
Georgia
Senta
S
Department of Biochemistry and Molecular Biology, University of Southern California, Developmental Biology Program, Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, California 90027, USA.
Bhushan
Anil
A
D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D002455:Cell Division / Q000502:physiology*; D056742:Cyclin D2; D016213:Cyclins / Q000235:genetics / Q000378:metabolism*; D005934:Glucagon / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D007328:Insulin / Q000378:metabolism; D007515:Islets of Langerhans / Q000166:cytology / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010179:Pancreas / Q000033:anatomy & histology / Q000254:growth & development* / Q000378:metabolism
C080336:CCND2 protein, human; D056742:Cyclin D2; D016213:Cyclins; D007328:Insulin; D005934:Glucagon; D005947:Glucose