CAVEOLIN-1 IN HUMAN PREECLAMPTIC PLACENTAS

CASTRO PARODI M; ABAN C; MARTINEZ N; HERLAX V; MATE S; FARINA M ; DAMIANO A

Simposio; VI LatinAmerican Symposium on Maternal-Fetal Interaction & Placenta; 2015

Caveolin-1 is a raft-associated protein involved in many cellular events as cell differentiation. It is thought that caveolin-1 may play an important role in the negative regulation of the cell cycle, retarding mitosis to halt proliferation. Emerging data establish that disturbances in trophoblast differentiation are related to pathological conditions such as preeclampsia. Unlike the situation reported in other differentiated cells, a normal syncytialization process has been associated with a reduction in the number of caveolae, and a decreased expression of caveolin-1. It is known that lipid rafts are membrane domains rich in sphingolipids and cholesterol. In preeclamptic placentas, we have previously found an increase in sphingomyelin in the apical membrane of syncytiotrophoblast without changes in cholesterol amount. However, the expression of caveolin-1 has not been investigated yet. Objective: To study the expression and localization of caveolin-1 in preeclamptic placentas. Methods: Caveolin-1 expression in normal (n¼8) and preeclamptic (n¼8) placentas was determined by RT-PCR, Western Blot and immunohistochemistry. Detergent-resistant Membranes (DRMs) were prepared from apical and basal vesicles from normal and preeclamptic placentas by sucrose gradient centrifugation and caveolin-1 protein expression was detected in each fraction. Results: At transcriptional levels, RT-PCR experiments showed no differences between normal and preeclamptic placentas. In normal placentas, caveolin-1 localized in the apical membrane of the syncytiotrophoblast and in the endothelium. However, in preeclamptic placentas, caveolin-1 was almost undetectable. Accordingly with this result, Western blots showed a significant decrease of caveolin-1 protein in the apical DRMs from preeclamptic placentas compared to normal ones. Conclusions: Our findings suggest that caveolin-1 was almost undetectable in preeclamptic placentas. Although in normal placenta, the reduction in caveolin-1 throughout pregnancy may simply be a feature of the loss of lateral cell membranes following cell fusion, in preeclamptic placentas the marked decreased of this protein may be associated with failures in the syncytialization process.