Problem: Toll-like receptors (TLRs) are expressed on placental cells. The aim of this study is to analyze signaling components activated in placenta cells after TLR ligand engagement.
Methods of study: In chorioncarcimoma cell lines the regulation of TLRs was determined by real time polymerase chain reaction as well as by fluorescence-activated cell sorter analysis. Activation of NF-κB was determined in a reporter assay system and the activation of the mitogen-activated protein kinase signaling pathways by immunoblot analysis.
Results: Both lipopolysaccharide (LPS) and DNA oligonucleotides containing unmethylated CpG motifs (CpG) induced the enhanced expression of TLR2 mRNA as well as a TLR2 surface protein expression. Functionally, incubation of JAR cells with microbial stimuli such as LPS activated NF-κB, as well as the phosphorylation of ERK1/2 and p38 MAP kinases and secretion of interleukin-8.
Conclusion: The functional expression of TLRs on placental cells may play an important role in the initiation of an immune response in the developing fetus.