Regulation of Interferon-Stimulated Genes in Peripheral Blood Leukocytes in Pregnant and Bred, Nonpregnant Dairy Cows

Abstract

In ruminants, pregnancy results in up-regulation of a large number of IFN-stimulated genes (ISG) in the uterus. Recently, one of these genes was also shown to increase in peripheral blood leukocytes (PBL) during early pregnancy in sheep. Our working hypothesis is that conceptus signaling activates maternal gene expression in PBL in dairy cattle. The objectives of this study were to characterize ISG expression in PBL from pregnant (n = 20) and bred, nonpregnant (n = 30) dairy cows. Steady-state levels of mRNA for Mx1, Mx2, beta2-microglobulin, ISG-15, IFN regulatory factor-1, and IFN regulatory factor-2 were quantified. Holstein cows were synchronized to estrus and artificially inseminated (d 0). Blood samples were collected (coccygeal venipuncture) on d 0 and 16, 18, and 20 d after insemination for progesterone analysis and PBL isolation. Pregnancy was confirmed by transrectal ultrasonography at approximately 40 d after breeding. A status x day interaction was detected for Mx1, Mx2, and ISG-15 gene expression. When analyzed within day, levels of mRNA for ISG-15 and Mx1 were greater in pregnant compared with bred, nonpregnant cows on d 18 and 20, respectively. Expression of the Mx2 gene increased in the pregnant group compared with bred, nonpregnant cows on d 16, 18, and 20 after insemination. beta2-Microglobulin, IFN regulatory factor-1, and IFN regulatory factor-2 were not different between groups. The results clearly indicated that components of the innate immune response are activated in PBL during the period of pregnancy recognition and early embryo signaling. The physiological implications of these changes on maternal immune function are as yet unknown; however, they do provide a unique opportunity to identify bred, nonpregnant, cows 18 d after insemination in dairy cattle.

The endometrium responds differently to cloned versus fertilized embryos

“…MX proteins belong to the antiviral proteins that are induced by type I IFN in response to infections caused by a wide range of singlestrand RNA viruses (24). Interestingly, in dairy cattle MX2 gene expression also is increased in peripheral blood leukocytes between days 16 and 20 of pregnancy, suggesting that the innate immune system is activated during early pregnancy (25). These results suggest that immune responses of the endometrium to the SCNTderived conceptus may be dysregulated, and such dysregulation has been suggested as a major cause of inadequate placentome development that leads to immune-mediated abortion in cloned pregnancies (26).…”

Upregulation of Interferon-stimulated Genes and Interleukin-10 in Peripheral Blood Immune Cells During Early Pregnancy in Dairy Cows

“…IFNT acts in the uterus around day 16 after insemination and prevents luteolysis by inhibiting prostaglandin F 2α release, resulting in the maintenance of corpus luteum function; therefore, this period is termed the maternal recognition period (MRP) [5]. IFNT induces the synthesis and secretion of IFN-stimulated genes (ISGs) such as ISG15, 2′,5′-oligoadenylate synthetase (OAS-1), IFN regulatory factor 1, Mx1 and Mx2 not only in the uterus but also in blood cells in ewes and cows [6][7][8][9][10]. In fact, in bovine peripheral blood leukocytes, ISG15 mRNA levels were higher in pregnant cows than in nonpregnant cows on days 18 and 20 after artificial insemination (AI) [7][8][9].…”

“…IFNT induces the synthesis and secretion of IFN-stimulated genes (ISGs) such as ISG15, 2′,5′-oligoadenylate synthetase (OAS-1), IFN regulatory factor 1, Mx1 and Mx2 not only in the uterus but also in blood cells in ewes and cows [6][7][8][9][10]. In fact, in bovine peripheral blood leukocytes, ISG15 mRNA levels were higher in pregnant cows than in nonpregnant cows on days 18 and 20 after artificial insemination (AI) [7][8][9]. Technology for the early detection of pregnancy is needed to identify nonpregnant cows and to synchronize and artificially inseminate these cows prior to the next ovulation, and many studies have focused on identifying easy-to-use markers of pregnancy using blood samples.…”

Exogenous hormonal manipulation to increase reproductive efficiency in dairy cows

“…Addition of progesterone to leukocytes cultured in vitro blunted the effect of IFN-α in stimulating mRNA expression for myxovirus resistance protein A (MxA; TAYEL et al, 2013), an ISG of the same family as Mx1 typically quantified in leukocytes of cattle (GIFFORD et al, 2007;. Interferon-τ and IFN-α are both type I IFN that interact with the same IFN receptor (ROBERTS et al, 1999).…”

“…Production of IFN-τ by the conceptus induces IFN-stimulated genes (ISG) in the endometrium such as myxovirus (influenza virus) resistance 1 (Mx1) and receptor transporter protein 4 (RTP4; HICKS et al, 2003;GIFFORD et al, 2008). Blood leukocytes harvested on d 16 or 19 after AI had increased expression of the ISG ubiquitin-like IFNstimulated gene 15-kDa protein (IGS15), Mx1, Mx2, and RTP4 (GIFFORD et al, 2007;, and leukocyte mRNA for ISG was correlated with the amount of IFN-τ in the uterus (MATSUYAMA et al, 2012). Interestingly, stimulation of conceptus development during pre-and peri-implantation resulted in increased expression of ISG in blood leukocytes and increased P/AI in lactating dairy cows .…”