Yoshida Saishu, Kato Takako, Kato Yukio
Organization for the Strategic Coordination of Research and Intellectual Property, Meiji University, Kanagawa 214-8571, Japan.
Institute of Reproduction and Endocrinology, Meiji University, Kanagawa 214-8571, Japan.
Int J Mol Sci. 2016 Jan 9;17(1):75. doi: 10.3390/ijms17010075.
The anterior lobe of the pituitary gland is a master endocrine tissue composed of five types of endocrine cells. Although the turnover rate of pituitary endocrine cells is as low as about 1.6% per day, recent studies have demonstrated that Sex-determining region Y-box 2 (SOX2)⁺-cells exist as pituitary stem/progenitor cells in the adult anterior lobe and contribute to cell regeneration. Notably, SOX2⁺-pituitary stem/progenitor cells form two types of niches in this tissue: the marginal cell layer (MCL-niche) and the dense cell clusters scattering in the parenchyma (parenchymal-niche). However, little is known about the mechanisms and factors for regulating the pituitary stem/progenitor cell niches, as well as the functional differences between the two types of niches. Elucidation of the regulatory mechanisms in the niches might enable us to understand the cell regeneration system that acts in accordance with physiological demands in the adult pituitary. In this review, so as to reveal the regulatory mechanisms of the two types of niche, we summarize the regulatory factors and their roles in the adult rodent pituitary niches by focusing on three components: soluble factors, cell surface proteins and extracellular matrixes.
垂体前叶是一种主要的内分泌组织，由五种内分泌细胞组成。尽管垂体内分泌细胞的更新率低至每天约1.6%，但最近的研究表明，性别决定区Y盒2（SOX2）⁺细胞作为垂体干/祖细胞存在于成年前叶中，并有助于细胞再生。值得注意的是，SOX2⁺垂体干/祖细胞在该组织中形成两种微环境：边缘细胞层（MCL微环境）和散布在实质中的致密细胞簇（实质微环境）。然而，关于调节垂体干/祖细胞微环境的机制和因素，以及两种微环境之间的功能差异，我们知之甚少。阐明微环境中的调节机制可能使我们能够理解在成年垂体中根据生理需求起作用的细胞再生系统。在这篇综述中，为了揭示两种微环境的调节机制，我们通过关注可溶性因子、细胞表面蛋白和细胞外基质这三个组成部分，总结了成年啮齿动物垂体微环境中的调节因子及其作用。
