No evidence for β cell neogenesis in murine adult pancreas
Xiangwei Xiao, … , John Wiersch, George K. Gittes
Xiangwei Xiao, … , John Wiersch, George K. Gittes
Published April 24, 2013
Citation Information: J Clin Invest. 2013;123(5):2207-2217. https://doi.org/10.1172/JCI66323.
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Research Article

No evidence for β cell neogenesis in murine adult pancreas

Abstract

Whether facultative β cell progenitors exist in the adult pancreas is a major unsolved question. To date, lineage-tracing studies have provided conflicting results. To track β cell neogenesis in vivo, we generated transgenic mice that transiently coexpress mTomato and GFP in a time-sensitive, nonconditional Cre-mediated manner, so that insulin-producing cells express GFP under control of the insulin promoter, while all other cells express mTomato (INSCremTmG mice). Newly differentiated β cells were detected by flow cytometry and fluorescence microscopy, taking advantage of their transient coexpression of GFP and mTomato fluorescent proteins. We found that β cell neogenesis predominantly occurs during embryogenesis, decreases dramatically shortly after birth, and is completely absent in adults across various models of β cell loss, β cell growth and regeneration, and inflammation. Moreover, we demonstrated upregulation of neurogenin 3 (NGN3) in both proliferating ducts and preexisting β cells in the ligated pancreatic tail after pancreatic ductal ligation. These results are consistent with some recent reports, but argue against the widely held belief that NGN3 marks cells undergoing endocrine neogenesis in the pancreas. Our data suggest that β cell neogenesis in the adult pancreas occurs rarely, if ever, under either normal or pathological conditions.

Authors

Xiangwei Xiao, Zean Chen, Chiyo Shiota, Krishna Prasadan, Ping Guo, Yousef El-Gohary, Jose Paredes, Carey Welsh, John Wiersch, George K. Gittes

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Figure 6

β cell neogenesis does not occur in the PDL pancreas.

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β cell neogenesis does not occur in the PDL pancreas. (A–C) Gross visual...
(A–C) Gross visualization of islets in the ligated tail (T) of the pancreas 1 week (A and B) and 4 weeks (C) after PDL due to the loss of acini, while the nonligated head (H) of the pancreas appears normal. B is a magnified view of the tail in A. Ligation position is indicated with a yellow line. (D) Confocal fluorescence images of cryosections from the ligated tail of INSCremTmG pancreas 1 week after PDL. Yellow cells were not detectable. (E) FACS of pancreatic digests from the ligated tail after PDL. Again, no yellow cells could be detected. (F) Gene expression of sorted red and green cells was analyzed by qPCR. Purity of the cells was ensured by checking for the expression of key transcripts. Ngn3 mRNA was highly upregulated in both the red and green cell populations in the ligated tail of the PDL pancreas, suggesting that NGN3 is activated both in non-β cells and in preexisting β cells after PDL. (G) Triple immunostaining for NGN3 (red), INS (green), and DBA (duct marker, blue) was performed, showing NGN3 positivity in duct cells and islets (mainly β cells) in the ligated tail, but not in any cells in the nonligated head of the PDL pancreas. All experiments were performed 5 times. Scale bars: 50 μm.