Gene Expression Profiling of LPS Responsive Genes in Human Trophoblast

Objectives: There is growing evidence that a number of complex human systemic diseases are caused by periodontal diseases. It has been suggested that maternal periodontal disease and incident progression are significant contributors to obstetric risk of preterm low birth weight. To elucidate the molecular basis of the mechanism, human trophoblast cell (BeWo) were treated with LPS isolated from Actinobaccilus actinomycetemcomitans, and gene expression profiles were monitored using DNA microarray technology. Effect of A. actinomycetemcomitans LPS administration to pregnant rats on low birth weight was also examined. Methods: BeWo were treated with A. actinomycetemcomitans LPS, and mRNA isolated, then mRNA levels were monitored using Affymetrix GeneChip (Human Genome U133 plus 2.0 array, ca. 47,000 genes). GeneChip data was analyzed using GeneSpring software and imported into Ingenuity Pathway Analysis (IPA) database to find the signal pathways involved. Altered mRNA levels in GeneChip results were confirmed by RT-PCR and real time PCR. Pregnant rats were intravenously injected with LPS and the body weight of newborn rats was measured. Then TUNEL method was used for detection of the apoptotic cells in placenta tissue of pregnant rats treated with A. actinomycetemcomitans LPS. Results: Intravenous administration of LPS resulted in newborn rats with a low birth weight and higher occurrence of apoptotic cells. GeneChip analysis showed that LPS treatment altered many gene expressions. IPA analysis for the function of reproductive system development revealed decreased mRNA levels of MSH5, FGFR1 and SMAD4. RT-PCR and Real-time PCR analysis successfully confirmed these mRNA level changes from GeneChip data. Conclusion: Since MSH5 play important roles in germ cells differentiation, further FGFR1 and SMAD4 are involved in cell proliferation, A. actinomycetemcomitans infection may induce apoptosis and inhibition of the proliferation of placenta cells through altering of these reduced gene expressions and contribute to low birth weight.