PDF(Pubmed)
Abstract：
Peroxisomal fatty acyl-CoA reductase 1 (FAR1) is a rate-limiting enzyme for ether lipid (EL) synthesis. Gene mutations in FAR1 cause a rare human disease. Furthermore, altered EL homeostasis has also been associated with various prevalent human diseases. Despite their importance in human health, the exact cellular functions of FAR1 and EL are not well-understood. Here, we report the generation and initial characterization of the first Far1 knockout (KO) mouse model. Far1 KO mice were subviable and displayed growth retardation. The adult KO male mice had smaller testes and were infertile. H&E and immunofluorescent staining showed fewer germ cells in seminiferous tubules. Round spermatids were present but no elongated spermatids or spermatozoa were observed, suggesting a spermatogenesis arrest at this stage. Large multi-nucleated giant cells (MGC) were found lining the lumen of seminiferous tubules with many of them undergoing apoptosis. The immunofluorescent signal of TEX14, an essential component of intercellular bridges (ICB) between developing germ cells, was greatly reduced and mislocalized in KO testis, suggesting the disrupted ICBs as an underlying cause of MGC formation. Integrative analysis of our total testis RNA-sequencing results and published single-cell RNA-sequencing data unveiled cell type-specific molecular alterations underlying the spermatogenesis arrest. Many genes essential for late germ cell development showed dramatic downregulation, whereas genes essential for extracellular matrix dynamics and cell-cell interactions were among the most upregulated genes. Together, this work identified the cell type-specific requirement of ELs in spermatogenesis and suggested a critical role of Far1/ELs in the formation/maintenance of ICB during meiosis.
摘要：
过氧化物酶体脂酰辅酶A还原酶1（FAR1）是醚脂质（EL）合成的限速酶。FAR1基因突变导致一种罕见的人类疾病。此外，改变的EL稳态也与各种流行的人类疾病有关。尽管它们对人类健康很重要，FAR1和EL的确切细胞功能尚不清楚。这里,我们报告了第一个Far1基因敲除（KO）小鼠模型的产生和初步表征。Far1KO小鼠是亚存活的并且表现出生长迟缓。成年KO雄性小鼠睾丸较小，不育。H＆E和免疫荧光染色显示生精管中生殖细胞较少。存在圆形精子，但未观察到细长的精子或精子，表明精子发生在这个阶段。在生精小管的内腔中发现了大的多核巨细胞（MGC），其中许多细胞正在凋亡。TEX14的免疫荧光信号是发育中的生殖细胞之间的细胞间桥（ICB）的重要组成部分，在KO睾丸中大大减少和错位，这表明ICBs的破坏是MGC形成的根本原因。对我们的睾丸总RNA测序结果和已发表的单细胞RNA测序数据的综合分析揭示了精子生成停滞的细胞类型特异性分子改变。许多对晚期生殖细胞发育至关重要的基因显示出戏剧性的下调，而细胞外基质动力学和细胞间相互作用所必需的基因是最上调的基因之一。一起,这项工作确定了精子发生中ELs的细胞类型特异性需求，并表明Far1/ELs在减数分裂过程中ICB的形成/维持中的关键作用。
