Hyperosmolarity Impairs Human Extravillous Trophoblast Differentiation by Caveolae Internalization.

Julieta Reppetti,Alicia E Damiano,Yollyseth Medina,Mariana Farina,Nora Alicia Martínez

doi:10.3389/fphys.2021.760163

Abstract

We recently reported that an intact caveolar structure is necessary for adequate cell migration and tubulogenesis of the human extravillous trophoblast (EVT) cells. Emerging evidence supports that hyperosmolarity induces the internalization of caveolae into the cytoplasm and accelerates their turnover. Furthermore, signaling pathways associated with the regulation of trophoblast differentiation are localized in caveolae. We hypothesized that hyperosmolarity impairs EVT differentiation and caveolae/caveolin−1 (Cav-1) participates in this process. EVT cells (Swan 71 cell line) were cultured in complete Dulbecco’s Modified Eagle Medium/Nutrient Mixture F-12 and exposed to hyperosmolar condition (generated by the addition of 100 mM sucrose). Hyperosmolarity altered the EVT cell migration and the formation of tube-like structures. In addition, cell invasion was decreased along with a reduction in the latent and active forms of matrix metalloproteinase-2 (MMP−2) secreted by these cells. With respect to Cav-1 protein abundance, we found that hyperosmolarity enhanced its degradation by the lysosomal pathway. Accordingly, in the hyperosmolar condition, we also observed a significant increase in the number of vacuoles and the internalization of the caveolae into the cytoplasm. Taken together, our findings suggest that hyperosmolarity may induce caveolae internalization and increase their turnover, compromising the normal differentiation of EVT cells.

Highlights

The success of pregnancy depends on the normal placental development that involves the differentiation of the highly proliferative and undifferentiated trophoblasts into two different general pathways
We recently reported in extravillous trophoblast (EVT) cells that osmolarities greater than 450 mOsM induce apoptosis by a mechanism that involves the activation of the transient receptor potential vanilloid-1 (TRPV-1) channel
Swan 71 cells were cultured in iso-osmolar condition (0 mM of sucrose—control cells) and hyperosmolar condition (100 mM of sucrose—hyperosmolarity-treated cells) for 24 h and cell viability was analyzed by MTT incorporation, a measure for mitochondrial dehydrogenase enzymatic activity

Summary

Introduction

The success of pregnancy depends on the normal placental development that involves the differentiation of the highly proliferative and undifferentiated trophoblasts into two different general pathways. Continuing on the path of differentiation, these inEVTs can become endovascular EVTs (enEVTs), which remodel the spiral uterine arteries by disruption of endothelium–myometrium interaction and replacing the endothelial cells, acquiring an “endothelial-like phenotype” (Bischof and Campana, 1996; Cartwright et al, 2010; Cartwright and Whitley, 2017). These events are not entirely clear, it is known that they are tightly regulated in a spatiotemporal manner. Defects in these highly-coordinated processes in the early first trimester of gestation can lead to pathologies associated with placental insufficiency as fetal death, fetal growth restriction (FGR), and preeclampsia (PE) (Cartwright et al, 2010; Ji et al, 2013)

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