Mulla Melissa J, Yu Andrew G, Cardenas Ingrid, Guller Seth, Panda Britta, Abrahams Vikki M
Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, New Haven, CT 06510, USA.
Am J Reprod Immunol. 2009 Apr;61(4):294-302. doi: 10.1111/j.1600-0897.2009.00694.x.
The cytoplasmic pattern recognition receptors, Nod1 and Nod2, are thought to be important for detecting intracellular bacteria. We have previously reported that first trimester trophoblast cells express Nod1 and Nod2, and that trophoblast Nod2 activation triggers an inflammatory response. The objectives of this study were to characterize the effects of Nod1 stimulation, and to determine the regulation of Nod1 and Nod2, in the trophoblast.
The effect of Nod1 activation on trophoblast cells was determined by analyzing the cytokine response following treatment with gamma-D-glutamyl-meso-diaminopimelic acid (iE-DAP). The regulation of Nod1 and Nod2 expression by trophoblast cells was evaluated by RT-PCR.
Treatment of trophoblast cells with iE-DAP significantly increased their production of cytokines and chemokines. In addition, Nod1 and Nod2 mRNA expression was upregulated following treatment of trophoblast cells with lipopolysaccharide (LPS), and this was significantly reduced by the presence of a NFkappaB inhibitor and a TLR4-dominant negative (DN).
This study demonstrates that LPS, through TLR4, increases trophoblast expression of Nod1 and Nod2 via the NFkappaB pathway; and that Nod1 is functional in the trophoblast. These findings suggest that extracellular recognition of bacterial LPS by TLR4 may prime the trophoblast in preparation for its cytoplasmic recognition of, and response to, bacterial peptides through the Nod proteins.
胞质模式识别受体Nod1和Nod2被认为在检测细胞内细菌方面很重要。我们之前曾报道，孕早期滋养层细胞表达Nod1和Nod2，且滋养层Nod2激活会引发炎症反应。本研究的目的是描述Nod1刺激的作用，并确定滋养层中Nod1和Nod2的调控机制。
通过分析用γ-D-谷氨酰-内消旋-二氨基庚二酸（iE-DAP）处理后细胞因子反应，来确定Nod1激活对滋养层细胞的影响。通过逆转录聚合酶链反应（RT-PCR）评估滋养层细胞对Nod1和Nod2表达的调控。
用iE-DAP处理滋养层细胞显著增加了细胞因子和趋化因子的产生。此外，用脂多糖（LPS）处理滋养层细胞后，Nod1和Nod2 mRNA表达上调，而NFκB抑制剂和TLR4显性阴性（DN）的存在可显著降低这种上调。
本研究表明，LPS通过TLR4，经由NFκB途径增加滋养层中Nod1和Nod2的表达；且Nod1在滋养层中具有功能。这些发现表明，TLR4对细菌LPS的细胞外识别可能使滋养层做好准备，以便通过Nod蛋白对细菌肽进行胞质识别和反应。
