INVESTIGADORES
MATE Sabina Maria
congresos y reuniones científicas
Título:
LIPID COMPOSITION AND BIOPHYSICAL PROPERTIES OF APICAL AND BASAL MEMBRANES OF PREECLAMPTIC PLACENTAS
Autor/es:
CASTRO-PARODI MAURICIO.; MARTÍNEZ NORA; MATÉ, SABINA M.1.; HERLAX VANESA; FARINA MARIANA; DAMIANO ALICIA
Lugar:
Mar del Plata
Reunión:
Congreso; VI Latin American Symposium on Maternal-Fetal Interaction and Placenta and V Latin American Symposium on Reproductive Immunology; 2015
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. The plasma membrane
of the 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 the amount of SMs 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 the Bligh-Dyer method and phospholipids
separated by thin layer chromatography and quantified by FiskeSubarrow.
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 in SM in the
apical membranes of syncytiotrophoblast without changes in cholesterol
amount. In addition, membrane fluidity decreased significantly and we
also found an increase in long and unsaturated fatty acids of SM.
Conclusions: Our results show that the apical membrane of the syncytiotrophoblast
is more rigid in the preeclamptic placentas than in normal
ones, due to an increase in SM content. We hypothesize that the increase in
the amount of a long and unsaturated SM molecular species disrupts the
ability of SM to assemble into lipid rafts in the luminal leaflet of the bilayer,
creating an unfavorable environment for appropriate location of placental
transporters in the plasma membrane.