The Effect of the Immunosuppressant Drug, Tacrolimus, on Nitric Oxide Production in the Immortalized First Trimester Extra-Villous Trophoblast Cells

Abstract

The remodeling of uterine spiral arteries and subsequent placental formation are crucial for normal growth and development of the fetus. These processes are heavily dependent on the functioning of the extra-villous trophoblast cells and their ability to invade into the maternal decidual blood vessels. Reduced trophoblast invasion and shallow spiral artery remodeling can lead to a number of gestational complications including intrauterine growth restriction (IUGR). Therapeutic intervention with low dose immunosuppressant tacrolimus was able to prevent implantation failure and IUGR in obese and diabetic mice. Treatment with tacrolimus successfully aided in spiral artery modification that was conducive to a successful pregnancy. Further, tacrolimus has shown promise in restoring trophoblast cell functioning in the immortalized first trimester HTR8/SVneo extra-villous trophoblast cells cultured under preeclampsia-like conditions in vitro. However, the mode of action of tacrolimus has yet to be elucidated. Here we attempt to uncover the mode of action of tacrolimus by examining its effects on eNOS activity within the trophoblast cells. Cells were treated with tacrolimus (10 ng/mL), L-NAME (40 nM/mL) or a combination of both and subjected to analysis by several functional assays. The data obtained in this study is suggesting that L-NAME treatment has inhibitory effects on the levels of the pPGR, pSTAT3 and NO within the HTR8/SVneo cells. The use of low-dose tacrolimus abrogated the suppressive effect of L-NAME and restored the levels of the pPGR, pSTAT3, and NO within the cells.