Regulation of Nod1 and Nod2 in first trimester trophoblast cells.
OBJECTIVE
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.


METHODS
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.


RESULTS
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).


CONCLUSIONS
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.
Mulla
Melissa J
MJ
Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, New Haven, CT 06510, USA.
Yu
Andrew G
AG
Cardenas
Ingrid
I
Guller
Seth
S
Panda
Britta
B
Abrahams
Vikki M
VM
D017209:Apoptosis; D001549:Benzamides / Q000494:pharmacology; D002478:Cells, Cultured; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D003960:Diaminopimelic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000276:immunology; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology; D016328:NF-kappa B / Q000037:antagonists & inhibitors; D053474:Nod1 Signaling Adaptor Protein / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D053473:Nod2 Signaling Adaptor Protein / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000276:immunology / Q000378:metabolism; D017384:Sequence Deletion; D015398:Signal Transduction; D013844:Thiazoles / Q000494:pharmacology; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D019076:Transgenes; D014327:Trophoblasts / Q000166:cytology / Q000276:immunology / Q000378:metabolism*
D001549:Benzamides; D016207:Cytokines; D008070:Lipopolysaccharides; D016328:NF-kappa B; C119067:NOD1 protein, human; C429018:NOD2 protein, human; D053474:Nod1 Signaling Adaptor Protein; D053473:Nod2 Signaling Adaptor Protein; C505226:SM 7368; C495345:TLR4 protein, human; D013844:Thiazoles; D051197:Toll-Like Receptor 4; D003960:Diaminopimelic Acid; C034331:N(2)-(gamma-D-glutamyl)-meso-2,2'-diaminopimelic acid