Expression of nuclear factor kappa B in ovine maternal inguinal lymph nodes during early pregnancy

Abstract

Background Pregnancy-induced immunological changes contribute to the maternal immune tolerance. Nuclear factor kappa B (NF-κB) pathway participates in regulating both innate and adaptive immunities, and lymph nodes play key roles in adaptive immune reaction. However, it is unclear whether early pregnancy changes the expression of NF-κB family in maternal lymph node in sheep. Methods In this study, the samples of inguinal lymph nodes were collected from ewes on day 16 of the estrous cycle, and on days 13, 16 and 25 of pregnancy, and expression of NF-κB family, including NF-κB p105 (NFKB1), NF-κB p100 (NFKB2), p65 (RELA), RelB (RELB) and c-Rel (REL), were analyzed through real-time quantitative PCR, Western blot and immunohistochemical analysis. Results The expression levels of NF-κB p105 and c-Rel downregulated, but NF-κB p100 upregulated on day 25 of pregnancy. The expression levels of p65, RelB and c-Rel peaked at day 13 of pregnancy, and expression level of RelB was higher during early pregnancy comparing to day 16 of the estrous cycle. In addition, p65 protein was located in the subcapsular sinus and lymph sinuses. Conclusion This paper reported for the first time that early pregnancy has effects on the expression of NF-κB family, which may contribute to the maternal immunoregulation through blood circulation and lymph circulation during early pregnancy in sheep.

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

“…The samples of spleens and lymph nodes were prepared as described previously [ 7 , 9 ], and total proteins were separated on polyacrylamide gels. Total proteins were transferred to PVDF membranes (Millipore, Bedford, MA, USA), and the membranes were incubated with primary antibodies overnight at 4 °C.…”

“…The fixed samples of spleens and lymph nodes were prepared as described previously [ 7 , 9 ]. Several sections were stained by hematoxylin and eosin (HE).…”

“…Nuclear factor kappa B (NF-κB) is implicated in both physiological and pathological processes; NF-κB regulation is essential during pregnancy, and dysregulation results in premature termination of pregnancy, with bad outcomes for the mother and the fetus [ 5 ]. Early pregnancy modulates the expression of NF-κB components in the maternal thymus, spleen, liver and inguinal lymph nodes, which is necessary for embryo implantation and pregnancy maintenance in sheep [ 6 , 7 , 8 , 9 ].…”

“…Furthermore, the expression of ISGs, progesterone receptor, prostaglandin synthases, Th cytokines, MT1, gonadotropin-releasing hormone and its receptor, and prolactin and its receptor are changed in lymph nodes during early pregnancy in sheep [ 24 , 25 , 28 , 29 , 30 , 31 , 32 ]. On the other hand, early pregnancy regulates the expression of Toll-like receptor signaling members, complement components, nuclear factor kappa B family and NOD receptors in the ovine maternal lymph nodes [ 9 , 33 , 34 , 35 ].…”

Early Pregnancy Modulates Expression of the Nod-like Receptor Family in Lymph Nodes of Ewes

“…Proteins of melatonin receptor 1, gonadotropin-releasing hormone and its receptor, prolactin and its receptor, and a cluster of differentiation 4 are increased in the lymph nodes during ovine early gestation [ 26 , 27 , 28 ]. Furthermore, gestation regulates expression of the Toll-like receptors (TLRs), TNF receptor-associated factor 6, IL-1 receptor-associated kinase 1 and myeloid differentiation primary response gene 88 [ 29 ], as well as the complement components C1q, C1r, C1s, C2, C3, C4a, C5b and C9 and the NF-κB family in maternal lymph nodes [ 30 , 31 ].…”