Molecular Cloning and Characterization of Prostaglandin (PG) Transporter in Ovine Endometrium: Role for Multiple Cell Signaling Pathways in Transport of PGF 2α

Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas 77843-4458, USA.
Endocrinology (Impact Factor: 4.5). 02/2008; 149(1):219-31. DOI: 10.1210/en.2007-1087
Source: PubMed


In ruminants, endometrial prostaglandin F(2alpha) (PGF(2alpha)) is the luteolytic hormone. Cellular transport of PGF(2alpha) in the uterine endometrium is critical for regulation of the estrous cycle. Molecular mechanisms responsible for control of PGF(2alpha) transport in endometrium during luteolysis are largely unknown. In the present study, we characterized the prostaglandin transporter (PGT) in ovine endometrium. Ovine PGT cDNA consists of 1935 nucleotides that encode 644 amino acids. In ovine endometria, PGT is highly expressed during the period of luteolysis, between d 14 and 16 of the estrous cycle, in luminal and glandular epithelia. Pharmacological and genomic inhibition of PGT indicates that it is responsible for influx and efflux of PGF(2alpha) in ovine endometrial epithelial cells. Inhibition of PGT during the period of luteolysis prevents the release of oxytocin-induced PGF(2alpha) pulses, and maintains functional corpus luteum and its secretion of progesterone. In ovine endometrial epithelial cells, protein kinase A and protein kinase C pathways are involved in regulating the influx of PGF(2alpha), whereas epidermal growth factor receptor pathways are implicated in regulation of influx and efflux of PGF(2alpha.) The ERK1/2 pathway is associated with efflux of PGF(2alpha), whereas Jun-amino-terminal kinase/stress-activated protein kinase pathways are involved in both efflux and influx of PGF(2alpha.) Phosphatidylinositol 3-kinase pathways are not involved in either influx or efflux of PGF(2alpha) in ovine endometrial epithelial cells. These are the first results to demonstrate a functional role for PGT in regulation of PGF(2alpha) efflux and influx in ovine endometrial cells that influence luteolytic mechanisms in ruminants.

Download full-text


Available from: Jehoon Lee,
  • Source
    • "Suggested transmembrane model of porcine SLCO2A1. This model is based on structural and hydropathy analyses of the amino acid sequence (as performed on the bovine and ovine orthologs [1,14]) and its homology with the other described orthologs (see Additional file 2). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Because prostaglandins are involved in many (patho)physiological processes, SLCO2A1 was already characterized in several species in an attempt to unravel specific processes/deficiencies. Here, we describe the molecular cloning and characterization of the porcine ortholog in order to evaluate its possible involvement in F4 enterotoxigenic E. coli mediated neonatal diarrhoea, based on a positional candidate gene approach study. Porcine SLCO2A1 is organized in 14 exons, containing an open reading frame of 1935 bp, encoding a 12-transmembrane organic anion cell surface transporter of 644 aa. The -388 to -5 upstream region comprises a (CpG)48 island containing a number of conserved promoter elements, including a TATA box. A potential alternative promoter region was found in the conserved -973 to -700 upstream region. No consensus polyadenylation signal was discovered in the 3' UTR. Repeat sequences were found in 15% of all the non coding sequences.As expected for a multifunctional protein, a wide tissue distribution was observed. mRNA expression was found in the adrenal gland, bladder, caecum, colon (centripetal coil/centrifugal coil), diaphragm, duodenum, gallbladder, heart, ileum, jejunum, kidney, liver, longissimus dorsi muscle, lung, lymph node, mesenterium, rectum, spleen, stomach, tongue and ureter, but not in the aorta, oesophagus and pancreas.The promoter region and the exons (including the splice sites) of SLCO2A1 were resequenced in 5 F4ab/ac receptor positive and 5 F4ab/ac receptor negative pigs. Two silent and 2 missense (both S --> L at position 360 and 633) mutations were found, but none was associated with the F4ab/ac receptor phenotype. In addition, no phenotype associated differential mRNA expression or alternative/abberant splicing/polyadenylation was found in the jejunum. The molecular cloning and characterization of porcine SLCO2A1 not only contributes to the already existing knowledge about the transporter in general, but enables studies on porcine prostaglandin related processes/deficiencies as patient and/or model. Here we examined its possible involvement as receptor in F4 enterotoxigenic E. coli mediated neonatal diarrhoea. Because no phenotype associated differences could be found in the gene sequence nor in its jejunal transcription profile of F4ab/ac receptor positive/negative pigs, SLCO2A1 can most likely be excluded as receptor for F4 bacteria.
    BMC Genetics 10/2009; 10(1):64. DOI:10.1186/1471-2156-10-64 · 2.40 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Endometriosis is a debilitating disease characterized by the presence of functional endometrial glandular epithelium and stroma outside the uterine cavity that affects up to 20% of women of child-bearing age. Cyclooxygenase-2 (COX-2), a rate-limiting enzyme in the biosynthesis of prostaglandin E(2) (PGE(2)), is highly expressed in endometriotic tissues and results in increased concentrations of peritoneal PGE(2) in women. In this study, we determined the expression of COX-2 protein in ectopic and eutopic endometria in humans and the role of COX-2 in endometriotic cell survival, migration, and invasion in humans. Our results indicate that COX-2 protein is abundantly expressed in ectopic endometria compared with eutopic endometria. Comparatively, expression of COX-2 protein is higher in eutopic endometria from women with endometriosis compared with women without endometriosis. Inhibition of COX-2 decreases survival, migration, and invasion of endometriotic cells that are associated with decreased production of PGE(2). Cell growth inhibitory effects of COX-2 inhibition/silencing are mediated through nuclear poly (ADP-ribose) polymerase-mediated apoptosis. Cell motility and invasion inhibitory effects of COX-2 inhibition/silencing are mediated through matrix metalloproteinase-2 and -9 activities. Interestingly, effects of COX-2 inhibition is more profound in endometriotic epithelial than in stromal cells. Furthermore, inhibition of COX-2 affects invasion rather than migration of endometriotic epithelial and stromal cells. It is the first evidence showing that inhibition of COX-2 decreases endometriotic epithelial and stromal cell survival, migration, and invasion in humans. Our results support the emerging concept that COX-2/PGE(2) promotes the pathophysiology and pathogenesis of endometriosis in humans.
    Endocrinology 04/2008; 149(3):1180-9. DOI:10.1210/en.2007-1168 · 4.50 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Prostaglandins (PG) belong to a diverse family of cell signaling molecules known as eicosanoids. Other members in this family include prostacyclins (PGI), thromboxanes (TX), and leukotrienes (LT). All eicosanoids (from eicosa-, Greek for “twenty”) are synthesized by oxygenation of 20-carbon essential fatty acids (EFA). There are three parallel pathways by which eicosanoids are produced depending on the starting EFA. In all these parallel pathways, eicosanoid production is mediated by the activity of two families of enzymes: cyclooxygenases and lypooxygenases. Cyclooxygenases, or COX, generate prostanoids, the collective term used for PG, PGI, and TX, while lypooxigenases generate the LT. Eicosanoids are found in all living cells; in mammals eicosanoids derived from arachidonic acid are primarily involved in inflammation, immunity, and in central nervous system functions. Eicosanoids derived from the other two EFA, Dihomo-gamma-linoleic acid (DGLA) and eicosapentenoic acid (PA) are inactive or even anti- inflammatory [1].
    Reproductive Endocrinology, 12/2008: pages 195-204;
Show more