Acid ceramidase is a novel factor required for early embryo survival
Acid ceramidase is a novel factor required for early embryo survival
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DOI：
10.1096/fj.06-7016com
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发表时间：
2007-05-01
期刊：
影响因子：
4.8
通讯作者：
Schuchman, Edward H.
中科院分区：
文献类型：
--
作者：
Eliyahu, Efrat;Park, Jae-Ho;Schuchman, Edward H.
最近的研究表明，脂质，神经酰胺，诱导默认的细胞凋亡过程中的鸡蛋。然而，新形成的胚胎如何克服这种命运还不清楚。酸性神经酰胺酶（AC）是参与神经酰胺代谢的关键调节酶，AC基因（Asah 1）突变导致法伯脂肪肉芽肿病，这是一种致命的人类遗传性疾病。我们以前的研究表明，AC敲除（Asah 1-/-）小鼠具有致死表型，在此我们揭示了这一观察的机制。建立了一种单细胞聚合酶链反应（PCR）基因分型方法，用于分析Asah 1 +/-互交的单个胚胎.结合Annexin V染色，该基因型分析表明Asah 1-/-胚胎不能存活超过2-细胞期，并经历凋亡死亡。值得注意的是，鞘氨醇-1-磷酸（S1 P）治疗早期2-细胞胚胎从Asah 1 +/-杂交拯救Asah 1-/-胚胎，并使他们的发展从2-细胞到4 - 8-细胞阶段。定量PCR还显示Asah 1基因在健康胚胎中的表达起始于2细胞期，与胚胎基因组激活（EGA）相一致。AC活性和Western印迹分析进一步证明了正常未受精卵中酶的高表达和活性，这可能在EGA之前为新形成的胚胎提供蛋白质。基于这些观察结果，我们认为AC是胚胎存活所需的重要因素，其功能是通过从新形成的胚胎中去除神经酰胺，从而抑制默认的凋亡途径。
Recent studies suggest that the lipid, ceramide, induces the default apoptosis process in eggs. Yet, it is obscure how newly formed embryos overcome this fate. Acid ceramidase ( AC) is a key regulatory enzyme involved in ceramide metabolism, and mutations in the AC gene ( Asah1) result in Farber Lipogranulomatosis, a fatal human genetic disorder. Our previous studies revealed that AC knockout ( Asah1-/-) mice had a lethal phenotype, and herein we reveal the mechanism underlying this observation. A single- cell, polymerase chain reaction ( PCR) genotyping method was developed to analyze individual embryos from Asah1 +/- intercrosses. Combined with Annexin V staining, this genotype analysis demonstrated that Asah1-/- embryos could not survive beyond the 2- cell stage, and underwent apoptotic death. Notably, sphingosine-1-phosphate ( S1P) treatment of early 2- cell embryos from the Asah1 +/- intercrosses rescued Asah1-/- embryos, and enabled their progression from the 2- cell to 4 - 8- cell stage. Quantitative PCR also revealed that expression of the Asah1 gene in healthy embryos was initiated at the 2- cell stage, coincident with embryonic genome activation ( EGA). AC activity and Western blot analyses further demonstrated high expression and activity of the enzyme in normal, unfertilized eggs, which likely provide the protein to newly formed embryos prior to EGA. Based on these observations, we suggest that AC is an essential factor required for embryo survival that functions by removing ceramide from the newly formed embryos, thus inhibiting the default apoptosis pathway.