earticle

영어

Uterine natural killer (uNK) cells are phenotypically and functionally specialized natural killer (NK) cells in the innate immune system. uNK cells are present at a high frequency in the uterine endometrium in humans and mice and have been shown to play a role both in regulating trophoblast invasion and in spiral artery remodeling. However, the function of uNK cells has not been well studied in pigs. Thus, to initiate the study on the role of uNK cells at the maternal-conceptus interface in pigs, this study determined the expression of several NK cell markers, including natural cytotoxicity triggering receptor 1 (NCR1), Fc fragment of IgG receptor III (FCGR3), neural cell adhesion molecule 1 (NCAM1), perforin 1 (PRF1) and granzyme B (GZMB) in the uterine endometrium during the estrous cycle and pregnancy in pigs. We obtained the endometrial tissues from gilts on day (D) 0, D3, D6, D9, D12, D15 and D18 of the estrous cycle and on D12, D15, D30, D60, D90 and D114 of pregnancy, and chorioallantoic tissues on D30, D60, D90 and D114 of pregnancy. Real-time RT-PCR analysis showed that the expression of NCR1, FCGR3, NCAM1, PRF1 and GZMB mRNAs was detected in the uterine endometrial tissues. Levels of NCR1, FCGR3, PRF1 and GZMB mRNAs in the uterine endometrium were highest on D15 of pregnancy. Levels of NCR1 mRNA were decreased toward term pregnancy. FCGR3 mRNA levels were constant during mid pregnancy. Expression levels of PRF1 and GZMB mRNA during pregnancy showed a biphasic pattern with the highest levels on D15 and D60 of pregnancy. However, levels of NCAM1 mRNA were highest on D12 of the estrous cycle. RT-PCR analysis showed that NCAM1 mRNA, but not NCR1, FCGR3, PRF1 and GZMB mRNAs, was detectable in conceptus on D12 and D15 of pregnancy. Chorioallantoic tissues also expressed NK cell markers, except NCR1, with increasing levels of FCGR3, PRF1, and GZMB mRNAs and decreasing levels of NCAM1 mRNA toward term pregnancy. These results indicate that NK cell markers are expressed in the uterine endometrium during the estrous cycle and pregnancy in a stage- and pregnancy status-dependent manner. NK cells may play an important role in the establishment and maintenance of pregnancy by regulating the endometrial immune environment in pigs. Further analysis of localization and function of NK cells at the maternal-conceptus interface is needed.