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.
Early gestation is critical for placentomal growth, differentiation, and vascularization, as well as fetal organogenesis. The fetal origins of adult disease hypothesis proposes that alterations in fetal nutrition and endocrine status result in developmental adaptations that permanently change structure, physiology, and metabolism, thereby predisposing individuals to cardiovascular, metabolic, and endocrine disease in adult life. Multiparous ewes were fed to 50% (nutrient restricted) or 100% (control fed) of total digestible nutrients from Days 28 to 78 of gestation. All ewes were weighed weekly and diets adjusted for individual weight loss or gain. Ewes were killed on Day 78 of gestation and gravid uteri recovered. Fetal body and organ weights were determined, and numbers, morphologies, diameters, and weights of all placentomes were obtained. From Day 28 to Day 78, restricted ewes lost 7.4% of body weight, while control ewes gained 7.5%. Maternal and fetal blood glucose concentrations were reduced in restricted versus control pregnancies. Fetuses were markedly smaller in the restricted group than in the control group. Further, restricted fetuses exhibited greater right- and left-ventricular and liver weights per unit fetal weight than control fetuses. No treatment differences were observed in any gross placentomal measurement. However, caruncular vascularity was enhanced in conceptuses from nutrient-restricted ewes but only in twin pregnancies. While these alterations in fetal/placental development may be beneficial to early fetal survival in the face of a nutrient restriction, their effects later in gestation as well as in postnatal life need further investigation.
The ruminant conceptus synthesizes and secretes interferon (IFN)-tau, which presumably acts via an intrauterine paracrine mechanism to signal maternal recognition of pregnancy. The aims of this study were to determine whether IFN-stimulated genes (ISG) such as ISG15 and OAS-1 are differentially expressed in blood cells circulating in the uterus of ewes; whether extrauterine components of the reproductive tract such as the corpus luteum (CL) also express mRNA for these ISG, and whether antiviral activity is greater in uterine vein than in uterine artery during early pregnancy. The concentrations of mRNA for both ISG were significantly greater (P < 0.0001) in endometrium and jugular blood of 15-d pregnant ewes than in nonpregnant ewes. ISG15 and OAS-1 mRNA concentrations were also greater (P < 0.05) in CL from 15-d pregnant ewes than in nonpregnant ewes. Immunohistochemistry revealed intense staining for ISG15 in large luteal cells on d 15 of pregnancy. Blood cells from uterine artery and vein of 15-d pregnant ewes had similar ISG15 and OAS-1 mRNA concentrations, suggesting that these cells were not conditioned by IFN-tau within the uterus. By using an antiviral assay, uterine venous blood was found to contain 500- to 1000-fold higher concentrations of bioactive IFN-tau than in uterine arterial blood on d 15 of pregnancy. It is concluded that uterine vein releases IFN-tau, which induces ISG in extrauterine tissues such as the CL during the time of maternal recognition of pregnancy.
The acceptor dependence on the glycosylation stereoselectivity is revealed by a systematic study employing model acceptors of gradually changing nucleophilicity.
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