INIBIOLP   05426
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE LA PLATA "PROF. DR. RODOLFO R. BRENNER"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Lipid composition and biophysical properties of apical and basal membranes of preeclamptic placentas
Autor/es:
CASTRO-PARODI MAURICIO; MARTINEZ, NORA; MATE, SABINA; HERLAX, VANESA; FARINA MARIANA; DAMIANO ALICIA E
Lugar:
Mar del Plata
Reunión:
Simposio; VI LatinAmerican Symposium on Maternal-Fetal Interaction & Placenta; 2015
Institución organizadora:
Placenta Association of the Americas- Grupo Latinoamericano de placenta
Resumen:
Transport activities together with other membrane-associated properties are greatly influenced and modulated by the physical state of the membrane lipid bilayer and by protein-lipid interactions. Plasma-membrane of syncytiotrophoblast is unusual in comparison to other cell types. The syncytiotrophoblast is a polarized epithelial layer of multinucleated syncytium, with its apical brush border membrane (BBM) facing the maternal circulation and the smooth basal membrane (BM) facing the fetal circulation. Sphingomyelins (SMs) and phosphatidylcholines (PCs) are major lipid classes in the mammalian cell plasma-membrane. In previous experiments, in normal placenta we found that SM amount is higher than in other tissues. In addition, accumulated evidence suggests that the expression of a variety of syncytiotrophoblast transporters, is reduced or abnormal in pathological placentas such as preeclamptic placentas. However, the inductor mechanism for these changes is unknown. OBJECTIVE: To analyze the lipid composition and biophysical properties of syncytiotrophoblast membranes of preeclamptic placentas. METHODS: Lipids were extracted by Bligh-Dyer method, phospholipids separated by thin layer chromatography and quantified by Fiske-Subarrow. Cholesterol was determined by a commercial kit. Membrane fluidity was evaluated by electron paramagnetic resonance. SM molecular species were analyzed and quantified by gas-liquid chromatography and mass spectrometry. RESULTS: In preeclamptic placentas, we observed an increase SM in the apical membranes of syncytiorophoblast without changes in cholesterol amount. In addition, its fluidity decreased significantly and we also found an increase in long and unsaturated fatty acids of SM. CONCLUSIONS: Our results show that apical membrane of syncytiotrophoblast is more rigid than normal ones, due to an increment on SM content. We hypothesize that the increment on the amount of a long and unsaturated SM molecular specie disrupts the ability of SM to assemble into lipid rafts in the luminal leaflet of the bilayer, creating an unfavorable environment for appropriated location of placental transporters in the plasma-membrane.