FGF8-FGFR1是保持小鼠精原干细胞未分化状态的生境因子

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FGF8-FGFR1 Signaling Acts as a Niche Factor for Maintaining Undifferentiated Spermatogonia in the Mouse1
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3 k. X) A& f$ L+ bPublished online before print October 30, 2014, doi: 10.1095/​biolreprod.114.121012
& F  C5 V* O# U6 HBiology of Reproduction December 1, 2014 vol. 91 no. 6 145
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  G+ y0 s" k7 G1 W+ g: O$ g7 U4 u. MABSTRACT
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In mammalian testes, spermatogonial stem cells (SSCs) maintain spermatogenesis over a long period of time by undergoing self-renewal and differentiation. SSCs are among the most primitive of spermatogenic cells (undifferentiated spermatogonia), and their activities are strictly regulated by extrinsic niche factors. However, the factors that constitute a testicular niche remain poorly understood. In this study, we demonstrate that fibroblast growth factor (FGF) signaling maintains undifferentiated spermatogonia through activating ERK1/2 signaling in vivo. Undifferentiated spermatogonia comprise GFRA1+ and NANOS3+ subpopulations, which are likely to undergo self-renewal and enter the differentiation pathway, respectively. In the testis, Fgfr1 was expressed in the entire population of undifferentiated spermatogonia, and deleting FGFR1 in spermatogenic cells partially inactivated ERK1/2 and resulted in reduced numbers of both GFRA1+ and NANOS3+ cells. In addition, Fgf8 was expressed in spermatogenic cells, and loss- and gain-of-function models of FGF8 demonstrated that FGF8 positively regulated the numbers of undifferentiated spermatogonia through FGFR1, particularly among NANOS3+ cells. Finally we show a possible involvement of FGF signaling in the reversion from NANOS3+ into GFRA1+ undifferentiated spermatogonia. Taken together, our data suggest that FGF signaling is an important component of the testicular niche and has a unique function for maintaining undifferentiated spermatogonia./ j# N/ N0 _4 q) B5 ?
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Key words: developmental biology knockout model Sertoli cells signal transduction spermatogonial stem cells transgenic model& }: s0 e! K6 p5 i9 R
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