Showing papers by "Fuller W. Bazer published in 2005"

Polyamine Synthesis from Proline in the Developing Porcine Placenta

Abstract: Polyamines (putrescine, spermidine, and spermine) are essential for placental growth and angiogenesis. However, little is known about polyamine synthesis in the porcine placenta during conceptus development. The present study was conducted to test the hypothesis that arginine and proline are the major sources of ornithine for placental polyamine production in pigs. Placentae, amniotic fluid, and allantoic fluid were obtained from gilts on Days 20, 30, 35, 40, 45, 50, 60, 90, and 110 of the 114-day gestation (n = 6 per day). Placentae as well as amniotic and allantoic fluids were analyzed for arginase, proline oxidase, ornithine aminotransferase (OAT), ornithine decarboxylase (ODC), proline transport, concentrations of amino acids and polyamines, and polyamine synthesis using established radiochemical and chromatographic methods. Neither arginase activity nor conversion of arginine into polyamines was detected in the porcine placenta. In contrast, both proline and ornithine were converted into putrescine, spermidine, and spermine in placental tissue throughout pregnancy. The activities of proline oxidase, OAT, and ODC as well as proline transport, polyamine synthesis from proline, and polyamine concentrations increased markedly between Days 20 and 40 of gestation, declined between Days 40 and 90 of gestation, and remained at the reduced level through Day 110 of gestation. Proline oxidase and OAT, but not arginase, were present in allantoic and amniotic fluids for the production of ornithine (the immediate substrate for polyamine synthesis). The activities of these two enzymes as well as the concentrations of ornithine and total polyamines in fetal fluids were highest at Day 40 but lowest at Days 20, 90, and 110 of gestation. These results indicate that proline is the major amino acid for polyamine synthesis in the porcine placenta and that the activity of this synthetic pathway is maximal during early pregnancy, when placental growth is most rapid. Our novel findings provide a new base of information for future studies to define the role of proline in fetoplacental growth and development.

Cathepsins in the ovine uterus: regulation by pregnancy, progesterone, and interferon tau.

Abstract: Cathepsins (CTS) are peptidases that have biological roles in degrading extracellular matrix, catabolism of intracellular proteins, and processing of prohormones. Expression of CTSB, CTSD, CTSH, CTSK, CTSL, CTSS, and CTSZ genes was detected in the endometria of cyclic and early pregnant ewes with distinct temporal and spatial expression patterns. In the d 18 and 20 conceptus, expression of CTSB, CTSD, CTSL, and CTSZ mRNA was detected in the trophectoderm. Of particular note, CTSL mRNA was the most abundant CTS mRNA in the ovine endometrium and detected only in the luminal epithelium and superficial glandular epithelium of cyclic and pregnant ewes. CTSL mRNA increased 8-fold between d 10 and 18 in endometria of pregnant ewes, whereas it declined between d 14 and 16 in cyclic ewes. CTSL protein was also detected in conceptus trophectoderm, and pro-CTSL was detected in uterine flushings from ewes between d 12 and 16 of pregnancy. In ovariectomized and catheterized ewes, CTSL mRNA in the endometrium was increased by progesterone and intrauterine injections of ovine interferon (IFN)tau. Other endometrial CTS genes were also regulated by progesterone alone (CTSB, CTSK, CTSS, and CTSZ) or progesterone and IFNtau (CTSH, CTSK, CTSS, and CTSZ). These results indicate that CTS of endometrial and conceptus origin may regulate endometrial remodeling and conceptus implantation, endometrial CTS genes are regulated by ovarian and placental hormones, and CTSL is a novel IFNtau-stimulated gene expressed only in luminal epithelium and superficial glandular epithelium of the endometrium.

Functional Effects of Transforming Growth Factor β on Adhesive Properties of Porcine Trophectoderm

Abstract: In pigs, expression and amounts of biologically active TGFβs at the conceptus-maternal interface increase significantly as conceptuses elongate and begin the implantation process. Before their activation, secreted TGFβs are noncovalently associated with their respective, isoform-specific latency-associated peptides (LAPs), which contain the Arg-Gly-Asp (RGD) amino acid sequence that serves as a ligand for numerous integrins. Objectives of this study were to determine whether TGFβ1 increases production of fibronectin by porcine trophectoderm, whether porcine trophectoderm adheres specifically to fibronectin and LAP, and whether functional interactions between porcine trophectoderm and the two TGFβ-associated proteins, fibronectin and LAP, are integrin mediated. Porcine trophectoderm cells (pTr2) were cultured in presence of TGFβ1, LAP, or pan-neutralizing anti-TGFβ antibody; TGFβ specifically increased (P < 0.05) fibronectin mRNA levels, as determined by Northern and slot blot analyses. Immunofluorescence ...

Interferon stimulated gene 15 conjugates to endometrial cytosolic proteins and is expressed at the uterine-placental interface throughout pregnancy in sheep.

Abstract: Interferon-stimulated gene 15 (ISG15) is a ubiquitin homolog expressed in uteri of ruminants in response to interferon (IFN)-τ and is also induced during pregnancy in the uteri of mice, pigs, humans, and baboons. This study examined expression of ISG15 and its conjugation to target proteins in the ovine uterus beyond the period of IFNτ secretion by the conceptus. Although steady-state levels of ISG15 mRNA decreased after d 25 of pregnancy, ISG15 persisted in endometrium through d 120. In situ hybridization and immunocytochemistry localized ISG15 across the entire uterine wall through d 25, after which expression was restricted to endometrial stroma along the maternal-placental interface. Western blots revealed ISG15 and ISG15-conjugated proteins in endometrium. Treatment of ovariectomized sheep with progesterone and IFNτ increased both free and conjugated ISG15. These results are the first to show in vivo regulation of ISG15 function (i.e. conjugation to target proteins) by a type I IFN in the uterus of a...

Effects of Keratinocyte Growth Factor on the Uterine Endometrial Epithelial Cells in Pigs

Abstract: Keratinocyte growth factor (KGF) functions in epithelial growth and differentiation in many tissues and organs. KGF is expressed in the uterine endometrial epithelial cells during the estrous cycle and pregnancy in pigs, and receptors for KGF (KGFR) are expressed by conceptus trophectoderm and endometrial epithelia. KGF has been shown to stimulate the proliferation and differentiation of conceptus trophectoderm. However, the role of KGF on the endometrial epithelial cells has not been determined. Therefore, this study determined the effect of KGF on proliferation and differentiation of endometrial epithelial cells in vitro and in vivo using an immortalized porcine luminal epithelial (pLE) cell line and KGF infusion into the uterine lumen of pigs between Days 9 and 12 of estrous cycle. Results showed that KGF did not stimulate proliferation of uterine endometrial epithelial cells in vitro and in vivo determined by the [ 3 H]thymidine incorporation assay and the proliferating cell nuclear antigen staining, respectively. Effects of KGF on expression of several markers for epithelial cell differentiation, including integrin receptor subunits a4, a5 and β1, plasmin/trypsin inhibitor, uteroferrin and retinol-binding protein were determined by RT-PCR, Northern and slot blot analyses, and immunohistochemisty, and KGF did not affect epithelial cell differentiation in vitro and in vivo. These results show that KGF does not induce epithelial cell proliferation and differentiation, suggesting that KGF produced by endometrial epithelial cells acts on conceptus trophectoderm in a paracrine manner rather than on endometrial epithelial cells in an autocrine manner.