Endometrial expression of progesterone-induced blocking factor and galectins-1, -3, -9, and -3 binding protein in the luteal phase and early pregnancy in cattle L. A. Okumu, 1 T. Fair, 1 J. Szekeres-Bartho, 2 A. M. O’Doherty, 1 M. A. Crowe, 1 J. F. Roche, 1 P. Lonergan, 1 and N. Forde 1 1 School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin, Ireland; and 2 Department of Medical Microbiology & Immunology, Medical School, Pecs University, Pecs, Hungary Submitted 16 December 2010; accepted in final form 19 May 2011 Okumu LA, Fair T, Szekeres-Bartho J, O’Doherty AM, Crowe MA, Roche JF, Lonergan P, Forde N. Endometrial expression of progesterone-induced blocking factor and galectins-1, -3, -9, and -3 binding protein in the luteal phase and early pregnancy in cattle. Physiol Genomics 43: 903–910, 2011. First published May 24, 2011; doi:10.1152/physiolgenomics.00251.2010.—Progesterone-induced block- ing factor (PIBF) and galectins modulate the maternal immune re- sponse during pregnancy. We hypothesized that the relative transcript abundance of the above genes would be different during the luteal phase/early pregnancy and would be affected by progesterone supple- mentation. To further test this, hypothesis protein expression analyses were carried out to evaluate the abundance and localization of LGALS9 and PIBF. Following estrus synchronization, heifers were inseminated (n = 140) or not (n = 70). Half the heifers in each status (cyclic or potentially pregnant) were randomly assigned to receive a progesterone-releasing intravaginal device (PRID) on day 3 after estrus, which elevated progesterone concentrations from day 3.5 to 8 (P  0.05), resulting in four treatment groups: cyclic and pregnant heifers, each with normal and high progesterone. After confirmation of pregnancy status in inseminated animals, uterine tissue was col- lected on days 5, 7, 13, or 16 of the luteal phase of the cycle/ pregnancy. Gene and protein expression was determined using Q-RT- PCR and IHC, respectively, on 5 heifers per treatment per time point (i.e., 80 in total). Progesterone concentrations did not affect expres- sion of any of the genes (P  0.05). LGALS9 and LGALS3BP were expressed at low levels in both cyclic and pregnant endometria until day 13. On day 16, expression increased only in the pregnant heifers (P  0.0001). LGALS1 and LGALS3 decreased on day 7 (P  0.0001) and remained low until day 16. Pregnancy had no effect on the expression of LGALS1, LGALS3, and PIBF. Additionally, LGALS9 and PIBF proteins were expressed in distinct uterine cell types. These results indicate that the galectins may be involved in uterine recep- tivity and/or implantation in heifers. bovine; uterus; early pregnancy; estrous cycle; progesterone DURING THE ESTROUS CYCLE, the uterus undergoes remodeling under the influence of estrogen and progesterone, to create an optimum environment for embryo survival and successful implantation. Numerous studies have identified a linear and quadratic relationship between progesterone concentrations during early pregnancy and probability of embryo survival/ pregnancy outcome in both lactating dairy cows and nonlac- tating heifers (12, 35, 52). Elevated concentrations of circulat- ing progesterone in the immediate postconception period have been associated with an advancement of conceptus elongation (8, 20, 46), an increase in interferon-tau (IFNT) production (32, 33) and higher pregnancy rates in cattle and sheep (35, 52). This advancement in conceptus elongation, due to elevated systemic progesterone concentrations, is thought to be medi- ated by the indirect action of progesterone on the uterine endometrium (10). Elevated progesterone, acting on the endo- metrium, actively downregulates the nuclear progesterone re- ceptor (38) and alters the timing and expression of genes thought to be important for establishing uterine receptivity to implantation (15, 17). In a high progesterone environment, the advanced conceptus, producing more IFNT, increases the ex- pression of genes involved in the maternal immune response that are required for successful pregnancy (16). Progesterone-induced blocking factor (PIBF) and members of the galectin family of proteins assert their actions on the maternal immune system by promoting a biased T-helper (TH) type 2 cytokine production, which favors pregnancy (6, 30, 43, 44). Progesterone, PIBF, and galectin 1 (lgals1) have been reported to act synergistically in mice to enhance fetal survival (6). Previous studies on the expression of some of the members of the galectin family in cattle relate to a single time point around the initiation of implantation, e.g., day 18 (2) or day 20 (34). In addition, the expression profile of LGALS1 has been reported during the estrous cycle (36). Galectins are members of the lectin family, characterized by a conserved carbohydrate recognition domain and high affinity for -galactosidases (6, 30, 41, 56), and display a wide tissue distribution in several species, where they mediate cell growth, adhesion, apoptosis, and immune modulation (22, 42) by recognizing carbohydrate groups in intracellular ligands, cell signaling receptors, and glycoproteins (24, 42). LGALS1 in humans (56), mice (6), and cattle (34, 36), galectin-3 (LGALS3) in humans (56), galectin-3 binding protein (LGALS3BP) in cattle (2), and galectin-9 (LGALS9) in humans (41, 48) and cattle (2) are expressed in the uterine endometrium. An additional member of the galectin family, galectin 15 (LGALS15), was identified in the bovine, ovine, and caprine genome (31). However, it is only expressed in sheep and goat endometrium (22, 31). Galectins lack a signal peptide for release and possess features that are characteristic of cytosolic proteins; hence, they are secreted from the cell via nonclassical pathways, enabling them to mediate both intra- and extracellular processes (30). They are implicated in the mediation of distinct functions in cell growth, adhesion, chemotaxis (41), apoptosis, immune function, and inflammation (21, 45), all of which are important processes for endometrial function. Indeed, LGALS15 has been Address for reprint requests and other correspondence: P. Lonergan, School of Agriculture, Food Science and Veterinary Medicine, Univ. College Dublin, Belfield, Dublin 4, Ireland (e-mail: pat.lonergan@ucd.ie). Physiol Genomics 43: 903–910, 2011. First published May 24, 2011; doi:10.1152/physiolgenomics.00251.2010. 1094-8341/11 Copyright © 2011 the American Physiological Society 903