earticle

영어

Atypical chemokine receptors (ACKRs) are chemokine receptors with seven transmembrane domains that fail to initiate classical signaling pathways after ligand binding. ACKRs comprises four receptors, ACKR1, ACKR2, ACKR3, and ACKR4, and are mainly expressed by non-leukocyte cell types, such as epithelial cells, lymphatic and vascular endothelial cells. ACKRs function as crucial regulatory components in a wide range of developmental, physiological and pathological events by controlling chemokine availability and function. However, expression and regulation of ACKR genes in the endometrium during the estrous cycle and pregnancy are not fully understood in pigs. Thus, this study determined expression of ACKR1, ACKR2, ACKR3, and ACKR4 in the porcine endometrium during the estrous cycle and pregnancy, and conceptus and chorioallantoic tissues during pregnancy. Real-time RT-PCR analysis showed levels of ACKR1, ACKR2, ACKR3, and ACKR4 mRNAs in the uterine endometrium during the estrous cycle changed with the highest abundance in diestrus or proestrus phases. Levels of ACKR3 mRNA were higher on Day 12 of estrous cycle than Day 12 of pregnancy, while expression of ACKR2 and ACKR4 mRNAs showed higher levels on Day 15 of pregnancy than Day 15 of the estrous cycle. In situ hybridization analysis showed that ACKR3 mRNA was localized specifically to luminal and glandular epithelial cells during the estrous cycle and early pregnancy. Conceptus and chorioallantoic tissues during pregnancy also expressed ACKR mRNA, but not ACKR4 mRNA. To investigate the effects of steroid hormones on the expression of ACKR mRNA, endometrial tissue explants were cultured in the presence of steroid hormones, estradiol and progesterone. The levels of ACKR2 and ACKR4 mRNAs were increased by progesterone. These results showed that ACKR genes regulated by progesterone are expressed in endometrium during estrous cycle and pregnancy, suggesting that ACKRs may play a key role in regulating chemokine action in the endometrium during the estrous cycle and pregnancy.