Nickkholgh B, Korver C M, van Daalen S K M, van Pelt A M M, Repping S
Center for Reproductive Medicine, Women's and Children's Hospital, Academic Medical Center, University of Amsterdam, Amsterdam 1105AZ, The Netherlands Present address: Wake Forest Institute for Regenerative Medicine, Wake Forest University school of Medicine, Winston-Salem, 27101 NC, USA.
Center for Reproductive Medicine, Women's and Children's Hospital, Academic Medical Center, University of Amsterdam, Amsterdam 1105AZ, The Netherlands.
Mol Hum Reprod. 2015 Jul;21(7):553-62. doi: 10.1093/molehr/gav022. Epub 2015 Apr 21.
Azoospermic factor c (AZFc) deletions are the underlying cause in 10% of azoo- or severe oligozoospermia. Through extensive molecular analysis the precise genetic content of the AZFc region and the origin of its deletion have been determined. However, little is known about the effect of AZFc deletions on the functionality of germ cells at various developmental steps. The presence of normal, fertilization-competent sperm in the ejaculate and/or testis of the majority of men with AZFc deletions suggests that the process of differentiation from spermatogonial stem cells (SSCs) to mature spermatozoa can take place in the absence of the AZFc region. To determine the functionality of AZFc-deleted spermatogonia, we compared in vitro propagated spermatogonia from six men with complete AZFc deletions with spermatogonia from three normozoospermic controls. We found that spermatogonia of AZFc-deleted men behave similar to controls during culture. Short-term (18 days) and long-term (48 days) culture of AZFc-deleted spermatogonia showed the same characteristics as non-deleted spermatogonia. This similarity was revealed by the same number of passages, the same germ cell clusters formation and similar level of genes expression of spermatogonial markers including ubiquitin carboxyl-terminal esterase L1 (UCHL1), zinc finger and BTB domain containing 16 (ZBTB16) and glial cell line-derived neurotrophic factor family receptor alpha 1 (GFRA1), as well as germ cell differentiation markers including signal transducer and activator of transcription 3 (STAT3), spermatogenesis and oogenesis specific basic helix-loophelix 2 (SOHLH2), v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (KIT) and synaptonemal complex protein 3 (SYCP3). The only exception was melanoma antigen family A4 (MAGEA4) which showed significantly lower expression in AZFc-deleted samples than controls in short-term culture while in long-term culture it was hardly detected in both AZFc-deleted and control spermatogonia. These data suggest that, at least in vitro, spermatogonia of AZFc-deleted men are functionally similar to spermatogonia from non-deleted men. Potentially, this enables treatment of men with AZFc deletions by propagating their SSCs in vitro and autotransplanting these SSCs back to the testes to increase sperm counts and restore fertility.
无精子因子c（AZFc）缺失是10%的无精子症或严重少精子症的潜在病因。通过广泛的分子分析，已确定AZFc区域的精确遗传内容及其缺失的起源。然而，关于AZFc缺失在生殖细胞不同发育阶段对其功能的影响，我们却知之甚少。大多数患有AZFc缺失的男性的精液和/或睾丸中存在正常的、具有受精能力的精子，这表明从精原干细胞（SSCs）到成熟精子的分化过程可以在没有AZFc区域的情况下发生。为了确定AZFc缺失的精原细胞的功能，我们比较了6名完全AZFc缺失男性体外增殖的精原细胞与3名正常精子生成男性的精原细胞。我们发现，在培养过程中，AZFc缺失男性的精原细胞表现与对照组相似。AZFc缺失的精原细胞短期（18天）和长期（48天）培养显示出与未缺失精原细胞相同的特征。这种相似性体现在传代次数相同、生殖细胞簇形成相同以及精原细胞标志物（包括泛素羧基末端酯酶L1（UCHL1）、含锌指和BTB结构域16（ZBTB16）以及胶质细胞源性神经营养因子家族受体α1（GFRA1））的基因表达水平相似，以及生殖细胞分化标志物（包括信号转导和转录激活因子3（STAT3）、生精和卵子发生特异性碱性螺旋-环-螺旋2（SOHLH2）、v-kit哈代-朱克曼4猫肉瘤病毒癌基因同源物（KIT）和联会复合体蛋白3（SYCP3））的基因表达水平相似。唯一的例外是黑色素瘤抗原家族A4（MAGEA4），在短期培养中，AZFc缺失样本中的表达明显低于对照组，而在长期培养中，在AZFc缺失和对照精原细胞中均几乎检测不到。这些数据表明，至少在体外，AZFc缺失男性的精原细胞在功能上与未缺失男性的精原细胞相似。这可能使患有AZFc缺失的男性通过体外扩增其精原干细胞并将这些精原干细胞自体移植回睾丸来增加精子数量并恢复生育能力。
