title: Differential regulation of placental amino acid transport by saturated and unsaturated fatty acids.
abstract: Fatty acids are critical for normal fetal development but may also influence placental function. We have previously reported that oleic acid (OA) stimulates amino acid transport in primary human trophoblasts (PHTs). In other tissues, saturated and unsaturated fatty acids have distinct effects on cellular signaling, for instance, palmitic acid (PA) but not OA reduces IκBα expression. We hypothesized that saturated and unsaturated fatty acids differentially affect trophoblast amino acid transport and cellular signaling. To test this hypothesis, PHTs were cultured in docosahexaenoic acid (DHA; 50 μM), OA (100 μM), or PA (100 μM). DHA and OA were also combined to test whether DHA could counteract the OA stimulatory effect on amino acid transport. The effects of fatty acids were compared against a vehicle control. Amino acid transport was measured by isotope-labeled tracers. Activation of inflammatory-related signaling pathways and the mechanistic target of rapamycin (mTOR) pathway were determined by Western blot analysis. Exposure of PHTs to DHA for 24 h reduced amino acid transport and phosphorylation of p38 MAPK, STAT3, mTOR, eukaryotic initiation factor 4E-binding protein 1, and ribosomal protein (rp)S6. In contrast, OA increased amino acid transport and phosphorylation of ERK, mTOR, S6 kinase 1, and rpS6. The combination of DHA with OA increased amino acid transport and rpS6 phosphorylation. PA did not affect amino acid transport but reduced IκBα expression. In conclusion, these fatty acids differentially regulated placental amino acid transport and cellular signaling. Taken together, these findings suggest that dietary fatty acids could alter the intrauterine environment by modifying placental function, thereby having long-lasting effects on the developing fetus.
authors.affiliation: Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, Texas sml60@medschl.cam.ac.uk.
authors.forename: Susanne
authors.initials: S
authors.lastname: Lager
authors.affiliation: Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, Texas.
authors.forename: Thomas
authors.initials: T
authors.lastname: Jansson
authors.affiliation: Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, Texas.
authors.forename: Theresa L
authors.initials: TL
authors.lastname: Powell
mesh_terms: D000263:Adenylate Kinase / Q000378:metabolism; D000596:Amino Acids / Q000378:metabolism*; D017209:Apoptosis; D001692:Biological Transport; D053148:Caspase 3 / Q000378:metabolism; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000378:metabolism; D004281:Docosahexaenoic Acids / Q000494:pharmacology / Q000502:physiology*; D006801:Humans; D019301:Oleic Acid / Q000494:pharmacology / Q000502:physiology*; D019308:Palmitic Acid / Q000494:pharmacology*; D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D014327:Trophoblasts / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D006063:Chorionic Gonadotropin; D004281:Docosahexaenoic Acids; D019301:Oleic Acid; D019308:Palmitic Acid; C546842:MTOR protein, human; D058570:TOR Serine-Threonine Kinases; D000263:Adenylate Kinase; C505407:CASP3 protein, human; D053148:Caspase 3
keywords: cell signaling; docosahexaenoic acid; oleic acid; palmitic acid; pregnancy