Fatty acid amide hydrolase deficiency limits early pregnancy events
Haibin Wang, Huirong Xie, Yong Guo, Hao Zhang, Toshifumi Takahashi, Philip J. Kingsley, Lawrence J. Marnett, Sanjoy K. Das, Benjamin F. Cravatt, Sudhansu K. Dey
Haibin Wang, Huirong Xie, Yong Guo, Hao Zhang, Toshifumi Takahashi, Philip J. Kingsley, Lawrence J. Marnett, Sanjoy K. Das, Benjamin F. Cravatt, Sudhansu K. Dey
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Research Article Reproductive biology

Fatty acid amide hydrolase deficiency limits early pregnancy events

Abstract

Synchronized preimplantation embryo development and passage through the oviduct into the uterus are prerequisites for implantation, dysregulation of which often leads to pregnancy failure in women. Cannabinoid/endocannabinoid signaling via cannabinoid receptor CB1 is known to influence early pregnancy. Here we provide evidence that a critical balance between anandamide synthesis by N-acylphosphatidylethanolamine–selective phospholipase D (NAPE-PLD) and its degradation by fatty acid amide hydrolase (FAAH) in mouse embryos and oviducts creates locally an appropriate “anandamide tone” for normal development of embryos and their oviductal transport. FAAH inactivation yielding higher anandamide or experimentally induced higher cannabinoid [(-)-Δ9-tetrahydrocannabinol] levels constrain preimplantation embryo development with aberrant expression of Cdx2, Nanog, and Oct3/4, genes known to direct lineage specification. Defective oviductal embryo transport arising from aberrant endocannabinoid signaling also led to deferred on-time implantation and poor pregnancy outcome. Intercrossing between wild-type and Faah–/– mice rescued developmental defects, not oviductal transport, implying that embryonic and maternal FAAH plays differential roles in these processes. The results suggest that FAAH is a key metabolic gatekeeper, regulating on-site anandamide tone to direct preimplantation events that determine the fate of pregnancy. This study uncovers what we believe to be a novel regulation of preimplantation processes, which could be clinically relevant for fertility regulation in women.

Authors

Haibin Wang, Huirong Xie, Yong Guo, Hao Zhang, Toshifumi Takahashi, Philip J. Kingsley, Lawrence J. Marnett, Sanjoy K. Das, Benjamin F. Cravatt, Sudhansu K. Dey

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Figure 2

Expression of Nape-pld and Faah in the oviduct and preimplantation embryos.

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Expression of Nape-pld and Faah in ...
(A) Spatiotemporal expression profiles of Nape-pld and Faah mRNA in the oviduct on days 1–4 (D1–4) of pregnancy. The results show that Nape-pld and Faah are expressed in a cell- and region-specific manner in the mouse oviduct during the preimplantation period. Higher levels of Nape-pld were detected in the oviduct epithelium at the isthmus region but much lower levels in the ampullary region. In contrast, Faah was primarily expressed in the epithelium at the ampullary region, with lower expression in the isthmus. Scale bar: 25 μm. (B and C) Cell-specific expression of Nape-pld and Faah mRNA and protein expression in preimplantation embryos. The results show that NAPE-PLD and FAAH are differentially expressed in the preimplantation embryos. While NAPE-PLD was expressed at all stages of preimplantation embryos, from fertilized 1-cell embryos to blastocysts, FAAH was expressed upon activation of the embryonic genome at the 2-cell stage and beyond. NAPE-PLD protein was detected in both nuclei and cytoplasm by this commercially available antibody. FAAH protein was detected in the cytoplasm and was primarily localized to outside cells in morulae and blastocysts. Images depict TRITC-labeled antigens as red, SYTO-13–labeled nuclei as green, and merge as yellow (scale bar: 50 μm). RT-cont, RNA without RT reaction; Pr-cont, primer control.