Expression of prostasin and protease nexin-1 in rhesus monkey (Macaca mulatta) endometrium and placenta during early pregnancy

Abstract

Serine proteases have been documented to play key roles in uterine matrix turnover and trophoblastic invasion during implantation. Roles of prostasin serine protease in these processes, however, are currently unclear. The present study was first conducted to investigate the colocalization of prostasin and its cognate serpin, protease nexin-1 (PN-1), in rhesus monkey endometrium and placenta on days 12, 18, and 26 of pregnancy by using in situ hybridization (ISH) and immunohistochemistry. With ISH, expression of prostasin mRNA was intensely localized in the glandular epithelium on days 12 and 18 and in the placental villi, trophoblastic column, trophoblastic shell, and fetal-maternal border on days 18 and 26. With the progress of pregnancy, expression level in the glandular epithelium was significantly decreased, and the accumulation in the placental compartments was further increased. In addition, the stroma and arterioles exhibited modest levels of prostasin signals. However, expression level of PN-1 in these compartments on adjacent sections in the three stages of early pregnancy was weak or below the level of detection. Prostasin protein expression in the endometrium was found to be consistent with the distribution patterns revealed in the ISH experiments. It may be suggested from these results that prostasin is involved in endometrial epithelial morphology establishment, tissue remodeling, and trophoblastic invasion during early pregnancy. The cognate serpin PN-1 was not coordinately expressed along with prostasin, creating a tissue environment favorable for proteolytic activities of prostasin during early pregnancy events.

Figure 1

In situ localization of prostasin and PN-1 mRNA in rhesus monkey endometrium and placenta on days 12 (D12), 18 (D18), and 26 (D26) of pregnancy. (A,B) Prostasin expression in the endometrium on D12. (C-E) Prostasin expression in the placenta and endometrium on D18. (F,G) PN-1 expression in the endometrium on D12. (H-J) PN-1 expression in the placenta and endometrium on D18. (K-N) Prostasin expression in the placenta and endometrium on D26. (P-S) PN-1 expression in the plancenta and endometrium on D26. (O,T) control (con) sections hybridized with sense probes of prostasin and PN-1, respectively, on D18. Results are representative of sections from three different monkeys. A, arteriole; FMB, fetal-maternal border; GE, glandular epithelium; PV, placental villi; S, stroma; TC, trophoblastic column; TS, trophoblastic shell. Bar = 100 μm.

Figure 2

Immunohistochemical localization of prostasin and PN-1 in rhesus monkey endometrium and placenta on days 12 (D12), 18 (D18), and 26 (D26) of pregnancy. (A,B) Prostasin expression in the endometrium on D12. (C-E) Prostasin expression in the placenta and endometrium on D18. (F,G) PN-1 expression in the endometrium on D12. (H-J) PN-1 expression in the placenta and endometrium on D18. (K-N) Prostasin expression in the placenta and endometrium on D26. (P-S) PN-1 expression in the plancenta and endometrium on D26. (O,T) control (con) sections immunostained with normal rabbit serum on D18. Results are representative of sections from three different monkeys. A, arteriole; FMB, fetal-maternal border; GE, glandular epithelium; PV, placental villi; S, stroma; TC, trophoblastic column; TS, trophoblastic shell. Bar = 100 μm.