Early Pregnancy Regulates Expression of IkappaB Family in Ovine Spleen and Lymph Nodes

Abstract

Early pregnancy modulates the maternal immune system, including the spleen and lymph nodes, which participate in maternal innate and adaptive immune responses. Methods: Ovine spleens and lymph nodes were sampled at day 16 of the estrous cycle, and at days 13, 16 and 25 of gestation, and qRT-PCR, Western blot and immunohistochemistry analysis were used to analyze the expression of the IκB family, including BCL-3, IκBα, IκBβ, IκBε, IKKγ, IκBNS and IκBζ. Early pregnancy induced expression of BCL-3, IκBα, IκBε, IKKγ and IκBζ, and expression of BCL-3, IκBβ and IκBNS peaked at day 16 of pregnancy in the spleen. However, early pregnancy suppressed the expression of BCL-3 and IκBNS, but stimulated the expression of IκBβ and IκBζ, and expression levels of IκBα, IκBβ, IκBε and IKKγ peaked in lymph nodes at days 13 and/or 16 of pregnancy. Early pregnancy changed the expression of the IκB family in the maternal spleen and lymph node in a tissue-specific manner, suggesting that the modulation of the IκB family may be involved in regulation of maternal functions of the spleen and lymph nodes, which are necessary for the establishment of maternal immune tolerance during early pregnancy in sheep.

Regulation of IkappaB Protein Expression by Early Gestation in the Thymus of Ewes

“…Early pregnancy modulates BCL-3 in the maternal liver, which regulates the maternal hepatic function to prepare for pregnancy establishment in the ovine [ 5 ]. BCL-3 expression increases in the maternal spleen but decreases in the maternal lymph nodes during the early gestation of ewes, suggesting that BCL-3 is implicated in the splenic adaptive immunity and immune tolerance of lymph nodes [ 11 ]. BCL-3 is expressed in thymocytes, which is associated with the DNA binding activity of NF-κB1 homodimers which affects the biological activities of NF-κB1 [ 26 ].…”

“…The IκBα level was higher in PBMCs from nonpregnant women than from pregnant females [ 9 ]. During ovine early gestation, IκBα expression was upregulated in the maternal spleen and increased but then decreased in the maternal lymph node, which could be associated with splenic B-cell maturation and maternal immunoregulation [ 11 ]. Early pregnancy stimulates IκBα expression in the ovine maternal liver, which is beneficial for pregnancy establishment [ 5 ].…”

“…In general, during early pregnancy, the serum estrogen concentration is low, but the progesterone concentration is high in ruminants. However, it has been reported that the IκBβ expression level peaks on DP16 in the maternal liver and lymph nodes during the early gestation of ewes, which are associated with the IFNT from conceptus, and are important for ovine pregnancy recognition [ 5 , 11 ]. The data showed that the IκBβ expression level was upregulated during early gestation, and the IκBβ protein was located in epithelial reticular cells, capillaries, and thymic corpuscles.…”

“…The experimental design was described previously [ 5 ]. Thymuses were collected after the females were euthanatized at days 13, 16, and 25 post-estrus for the pregnant ewes and on day 16 post-estrus for the nonpregnant ewes, as described previously [ 11 ]. The euthanasia of the ewes was performed by an experienced person to cut both the carotid arteries and jugular veins to bleed out the animals after electrical stunning.…”

“…The plasma IκBα level is downregulated in preeclamptic females compared with normotensive pregnant females; however, there is no significant difference in the plasma IκBα level between human immunodeficiency virus (HIV) positive and HIV-negative pregnant women [ 10 ]. Our previous studies reported that the expression of IκB proteins in ovine maternal liver, spleen, and lymph nodes was modulated during early pregnancy, which is associated with ovine maternal immune tolerance [ 5 , 11 ].…”