Sharma Swati, Portela Joana M D, Langenstroth-Röwer Daniel, Wistuba Joachim, Neuhaus Nina, Schlatt Stefan
Center of Reproductive Medicine and Andrology, Institute of Reproductive and Regenerative Medicine, Albert Schweitzer Campus 1, Building D11, Münster, Germany.
These authors contributed equally to this work.
Primate Biol. 2017 Sep 22;4(2):173-184. doi: 10.5194/pb-4-173-2017. eCollection 2017.
Over the past few decades, several studies have attempted to decipher the biology of mammalian germline stem cells (GSCs). These studies provide evidence that regulatory mechanisms for germ cell specification and migration are evolutionarily conserved across species. The characteristics and functions of primate GSCs are highly distinct from rodent species; therefore the findings from rodent models cannot be extrapolated to primates. Due to limited availability of human embryonic and testicular samples for research purposes, two non-human primate models (marmoset and macaque monkeys) are extensively employed to understand human germline development and differentiation. This review provides a broader introduction to the in vivo and in vitro germline stem cell terminology from primordial to differentiating germ cells. Primordial germ cells (PGCs) are the most immature germ cells colonizing the gonad prior to sex differentiation into testes or ovaries. PGC specification and migratory patterns among different primate species are compared in the review. It also reports the distinctions and similarities in expression patterns of pluripotency markers (OCT4A, NANOG, SALL4 and LIN28) during embryonic developmental stages, among marmosets, macaques and humans. This review presents a comparative summary with immunohistochemical and molecular evidence of germ cell marker expression patterns during postnatal developmental stages, among humans and non-human primates. Furthermore, it reports findings from the recent literature investigating the plasticity behavior of germ cells and stem cells in other organs of humans and monkeys. The use of non-human primate models would enable bridging the knowledge gap in primate GSC research and understanding the mechanisms involved in germline development. Reported similarities in regulatory mechanisms and germ cell expression profile in primates demonstrate the preclinical significance of monkey models for development of human fertility preservation strategies.
在过去几十年中，多项研究试图破解哺乳动物生殖系干细胞（GSCs）的生物学特性。这些研究表明，生殖细胞特化和迁移的调控机制在物种进化过程中是保守的。灵长类GSCs的特征和功能与啮齿类动物有很大不同；因此，从啮齿类动物模型得出的研究结果不能外推至灵长类动物。由于用于研究目的的人类胚胎和睾丸样本有限，两种非人类灵长类动物模型（狨猴和猕猴）被广泛用于了解人类生殖系的发育和分化。本综述对从原始生殖细胞到分化生殖细胞的体内和体外生殖系干细胞术语进行了更广泛的介绍。原始生殖细胞（PGCs）是在性别分化为睾丸或卵巢之前定殖于性腺的最不成熟生殖细胞。本综述比较了不同灵长类物种中PGC的特化和迁移模式。它还报告了狨猴、猕猴和人类在胚胎发育阶段多能性标志物（OCT4A、NANOG、SALL4和LIN28）表达模式的异同。本综述通过免疫组织化学和分子证据，对人类和非人类灵长类动物出生后发育阶段生殖细胞标志物表达模式进行了比较总结。此外，它还报告了最近文献中关于人类和猴子其他器官中生殖细胞和干细胞可塑性行为的研究结果。使用非人类灵长类动物模型将有助于弥合灵长类GSC研究中的知识差距，并了解生殖系发育所涉及的机制。灵长类动物在调控机制和生殖细胞表达谱方面的相似性表明，猴子模型在人类生育力保存策略开发方面具有临床前意义。
