Stem Cell Research (Sep 2016)

Isolation of adult pituitary stem/progenitor cell clusters located in the parenchyma of the rat anterior lobe

  • Saishu Yoshida,
  • Naoto Nishimura,
  • Hiroki Ueharu,
  • Naoko Kanno,
  • Masashi Higuchi,
  • Kotaro Horiguchi,
  • Takako Kato,
  • Yukio Kato

DOI
https://doi.org/10.1016/j.scr.2016.08.016
Journal volume & issue
Vol. 17, no. 2
pp. 318 – 329

Abstract

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Recent studies have demonstrated that Sox2-expressing stem/progenitor cells play roles in the pituitary cell turnover. Two types of niches have been proposed for stem/progenitor cells, the marginal cell layer (MCL) and the dense cell clusters in the parenchyma. Among them, the appearance of the parenchymal-niche only after birth indicates that this niche is involved in the cell turnover required for the postnatal pituitary. However, little is known about the roles of the parenchymal-niche and its regulation. The present study aimed to isolate pituitary stem/progenitor cells from the parenchymal-niche in the adult rat pituitary. Cell dispersion by stepwise treatment with proteases allowed the isolation of dense cell clusters. Immunocytochemistry demonstrated that clusters are universally composed of SOX2-positive cells, and most of them are positive for PROP1. Taken together with the anatomical analysis, we concluded that the isolated clusters are the parenchymal stem/progenitor cell (PS)-clusters, not the MCL-one. PS-clusters cultivated by serum-free overlay 3-dimensional culture maintained their stemness, and treatment with bFGF and EGF induced cyst-formation. Moreover, PS-clusters demonstrated some differentiation capacity with GSK3β-inhibitor treatment. Collectively, the present study demonstrates a simple method for isolating stem/progenitor cells from the parenchymal-niche, and provides tools to analyze the factors for regulating the pituitary niches.

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