Insulin-positive, Glut2-low cells present within mouse pancreas exhibit lineage plasticity and are enriched within extra-islet endocrine cell clusters

Abstract

Regeneration of insulin-producing β-cells from resident pancreas progenitors requires an understanding of both progenitor identity and lineage plasticity. One model suggested that a rare β-cell sub-population within islets demonstrated multi-lineage plasticity. We hypothesized that β-cells from young mice (postnatal day 7, P7) exhibit such plasticity and used a model of islet dedifferentiation toward a ductal epithelial-cell phenotype to test this theory. RIPCre;Z/AP(+/+) mice were used to lineage trace the fate of β-cells during dedifferentiation culture by a human placental alkaline phosphatase (HPAP) reporter. There was a significant loss of HPAP-expressing β-cells in culture, but remaining HPAP(+) cells lost insulin expression while gaining expression of the epithelial duct cell marker cytokeratin-19 (Ck19). Flow cytometry and recovery of β-cell subpopulations from whole pancreas vs. islets suggest that the HPAP(+)Ck19(+) cells had derived from insulin-positive, glucose-transporter-2-low (Ins(+)Glut2(LO)) cells, representing 3.5% of all insulin-expressing cells. The majority of these cells were found outside of islets within clusters of <5 β-cells. These insulin(+)Glut2(LO) cells demonstrated a greater proliferation rate in vivo and in vitro as compared to insulin(+)Glut2(+) cells at P7, were retained into adulthood, and a subset differentiated into endocrine, ductal, and neural lineages, illustrating substantial plasticity. Results were confirmed using RIPCre;ROSA- eYFP mice. Quantitative PCR data indicated these cells possess an immature β-cell phenotype. These Ins(+)Glut2(LO) cells may represent a resident population of cells capable of forming new, functional β-cells, and which may be potentially exploited for regenerative therapies in the future.

Virgin Beta Cells Persist throughout Life at a Neogenic Niche within Pancreatic Islets

“…Insulin-expressing Pancreatic Multipotent Progenitor cells (PMPs) were reported that are capable of extensive self-replication, self-renewal and contribute to multiple pancreatic and neural cell types (Smukler et al, 2011). These and similar cells found in small clusters outside of normal islets (Beamish et al, 2016) share a lack of cell-surface Glut2 with the immature beta cells we discovered at the niche. However, the genes enriched in the PMP transcriptome (Razavi et al, 2015) demonstrate virtually no overlap with those enriched in immature beta cells ( Figure S4).…”

A mouse model of gestational glucose intolerance through exposure to a low protein diet during fetal and neonatal development

“…Pancreata were removed for fixation in 4% paraformaldehyde and sectioned for histology as previously described (Beamish et al . ). At least three 7 µm‐thick cryosections (replicates) were cut from each pancreas with an interval between each section >100 µm.…”

Variability in endocrine cell identity in patients with chronic pancreatitis undergoing islet autotransplantation

“…7 Insulin resistance was defined as HOMA-IR >2. 12 Data were expressed as mean ± SEM of variance within islets in each sample. 9 A proinsulin value >10 pmol/L has been reported to be an independent indicator of IR.…”