Habayeb Osama M H, Taylor Anthony H, Bell Stephen C, Taylor David J, Konje Justin C
Endocannabinoid Research Group, Reproductive Sciences Section, Department of Cancer Studies and Molecular Medicine, University of Leicester, Leicester LE2 7LX, United Kingdom.
Endocrinology. 2008 Oct;149(10):5052-60. doi: 10.1210/en.2007-1799. Epub 2008 Jul 3.
The endocannabinoid, anandamide, which binds to two major receptor proteins, the cannabinoid receptors (CBs) 1 and 2 (CB1 and CB2), has been shown to play a role in first trimester miscarriage possibly through impairment of the developing trophoblast. Although the precise molecular mechanisms underlying this are unknown, plasma anandamide levels are known to be regulated by the progesterone-induced enzyme, fatty acid amide hydrolase (FAAH). Here, we tested the hypothesis that temporal-spatial expression of FAAH, CB1, and CB2 is regulated during early pregnancy and that anandamide detrimentally alters trophoblast proliferation. Transcripts for CB1, CB2, and FAAH were demonstrated in first trimester trophoblast extracts with only the CB1 transcript being significantly regulated. The significant 4.7-fold increase in expression at wk 10 gestation was reduced to 8.9% of the peak value by wk 12. Transcripts for CB2 showed a similar pattern of expression but were not significantly induced. By contrast, FAAH transcript levels appeared to increase toward the end of the first trimester, but again did not reach significance. These observations were supported by immunohistochemical studies that demonstrated a similar pattern of expression at the protein level, with cellular localization for all three proteins concentrated within the syncytiotrophoblast layer. Anandamide also prevented BeWo trophoblast cell proliferation in a dose-dependent manner, with a 50-60% significant inhibition of cell proliferation with concentrations in excess of 3 mum. This effect was mediated through CB2. Together, these data provide insights into how elevated plasma anandamide levels increase the risk of first trimester miscarriage.
内源性大麻素花生四烯乙醇胺可与两种主要受体蛋白，即大麻素受体（CB）1和CB2（CB1和CB2）结合，研究表明其可能通过损害发育中的滋养层细胞在孕早期流产中发挥作用。尽管其确切的分子机制尚不清楚，但已知血浆花生四烯乙醇胺水平受孕酮诱导的脂肪酸酰胺水解酶（FAAH）调节。在此，我们验证了以下假设：FAAH、CB1和CB2的时空表达在妊娠早期受到调节；花生四烯乙醇胺会对滋养层细胞增殖产生不利影响。在孕早期滋养层提取物中检测到了CB1、CB2和FAAH的转录本，只有CB1转录本受到显著调节。妊娠第10周时表达显著增加4.7倍，但到第12周时降至峰值的8.9%。CB2转录本显示出类似的表达模式，但未被显著诱导。相比之下，FAAH转录本水平在孕早期接近尾声时似乎有所增加，但同样未达到显著水平。免疫组化研究支持了这些观察结果，其显示所有三种蛋白在蛋白水平上具有类似的表达模式，且三种蛋白的细胞定位均集中在合体滋养层。花生四烯乙醇胺还以剂量依赖的方式抑制BeWo滋养层细胞增殖，浓度超过3 μM时可显著抑制细胞增殖50%-60%。这种作用是通过CB2介导的。总之，这些数据为血浆花生四烯乙醇胺水平升高如何增加孕早期流产风险提供了见解。
