Submission Date: Aug 24, 2020

Summary: Pancreatic islets adapt to insulin resistance of pregnancy by up regulating beta-cell proliferation and increase insulin secretion. Previously, we found that prolactin receptor (Prlr) signaling is important for this process, as heterozygous prolactin receptor-null (Prlr+/-) mice are glucose intolerant, had a lower number of beta cells and lower serum insulin levels than wild type mice during pregnancy. However, since Prlr expression is ubiquitous, to determine its beta-cell-specific effects, we generated a transgenic mouse with a floxed Prlr allele under the control of an inducible promoter, i.e. bPrlR-/- mice, allowing conditional deletion of Prlr from beta cells in adult mice. In this study, we found that beta-cell-specific Prlr reduction resulted in elevated blood glucose during pregnancy. Similar to our previous finding in mice with global Prlr reduction, beta-cell-specific Prlr loss led to a lower beta-cell mass and a lower in vivo insulin level during pregnancy. However, these islets do not have an intrinsic insulin secretion defect when tested in vitro. Interestingly, when we compared the islet gene expression profile, using islets isolated from mice with global versus beta-cell-specific Prlr reduction, we found differences in expression of genes that regulate apoptosis, synaptic vesicle function and neuronal development. Indeed, islets from pregnant Prlr+/- mice are more susceptible glucolipotoxicity than bPrlR+/- islets. These observations suggest that Prlr has both cell-autonomous and non-cell-autonomous effect on beta cells, beyond its regulation of pro-proliferative genes.

GEO Accession ID: GSE156774

PMID: 33990661