Uterine-conceptus interactions and reproductive failure in cattle

Abstract

The dialogue between trophectoderm cells of the conceptus and epithelial cells of the endometrium is critical to CL maintenance and embryo survival. The signal transduction mechanisms by which bovine interferon (IFN)-τ regulates cyclooxygenase (COX)-2 expression and secretion of prostaglandin F2α (PGF2α) in bovine endometrial (BEND) cells is examined. Stimulation of Protein Kinase C with a phorbol ester (phorbol 12, 13 dibutyrate [PDBu]) activates COX-2 gene expression and PGF2α secretion via the mitogen-activated protein kinase (MAPK) pathway. Interferon-τ attenuates PDBu activation of PGF2α secretion, but this inhibitory effect appears to be independent of the MAPK pathway. Embryonic IFN-τ acting through a Type I IFN receptor, activates the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway resulting in activation or repression of interferon-stimulated genes. Experimental evidence is provided that IFN-τ regulation of STATs regulates gene expression of COX-2 in a manner that decreases secretion of PGF2α. Maternal regulation of the antiluteolytic pathway is discussed relative to the ability of the polyunsaturated fatty acid, eicosapentaenoic (EPA), to decrease endometrial secretion of PGF2α and progesterone to increase both conceptus development and IFN-τ secretion. © 2001 by Elsevier Science Inc.