The expression patterns of IL-1β and IL-10 and their relation to CYP epoxygenases in normal human placenta

The success of pregnancy depends on the regulation of immunological processes in the placenta. Important mediators of an immune response include pro- and anti-inflammatory interleukins which may be regulated by CYP epoxygenases and their metabolites. The relation between interleukins and CYP epoxygenases expression in human placenta has not yet been studied vastly.

We investigated the expression patterns of IL-1β and IL-10 in embryonic (n=8), early foetal (n=16) and term (n=7) human placenta tissue by an immunohistochemical method and evaluated the results by Kruskal-Wallis test. The obtained data was correlated using Spearman's correlation coefficient to our previously published data of CYP epoxygenases expression in the same samples. To confirm that Hofbauer cells express IL-10 and IL-1β as well as CYP2C8 and IL-10 together, and thus there is a relation between proteins of interests, we used multiplex immunofluorescent staining.

The expression of IL-1β decreased with gestational age in cytotrophoblast, syncytiotrophoblast, as well as in Hofbauer cells whilst IL-10 decreased in cytotrophoblast, remained at the same levels in syncytiotrophoblast and increased in Hofbauer cells. In trophoblast cells, we found a statistically significant positive correlation between the expression of CYP2J2 and CYP2C9 with IL-1β, whereas there was no relation between IL-10 and any of the tested CYP epoxygenases. In Hofbauer cells, we found a significant positive correlation between CYP2C8 and IL-10 and a significant negative correlation between CYP2C8 and IL-1β.

Our results showed that the exact role and relation of interleukins and CYP epoxygenases and their metabolites is dependent on their respective cellular context. Because of IL-10, IL-1β, as well as HBCs play a role in various pathological conditions, further investigation of the exact role of CYP epoxygenase, interleukins and their relations is needed.