SPAK-dependent cotransporter activity mediates capillary adhesion and pressure during glioblastoma migration in confined spaces.

The invasive potential of glioblastoma cells is attributed to large changes in pressure and volume, driven by diverse elements, including the cytoskeleton and ion cotransporters.  However, how the cell actuates changes in pressure and volume in confinement, and how these changes contribute to invasive motion is unclear. Here, we inhibited SPAK activity, with known impacts on the cytoskeleton and cotransporter activity and explored its role on the migration of glioblastoma cells in confining microchannels to model invasive spread through brain tissue. First, we found that confinement altered cell shape, inducing a transition in morphology that resembled droplet interactions with a capillary vessel, from "wetting" (more adherent) at low confinement, to "nonwetting" (less adherent) at high confinement. This transition was marked by a change from negative to positive pressure by the cells to the confining walls, and an increase in migration speed. Second, we found that the SPAK pathway impacted the migration speed in different ways dependent upon the extent of wetting. For nonwetting cells, SPAK inhibition increased cell-surface tension and cotransporter activity. By contrast, for wetting cells, it also reduced myosin II and YAP phosphorylation. In both cases, membrane-to-cortex attachment is dramatically reduced. Thus, our results suggest that SPAK inhibition differentially coordinates cotransporter and cytoskeleton-induced forces, to impact glioblastoma migration depending on the extent of confinement.

Extracellular vesicles: Focus on peri-implantation period of pregnancy in pigs.

The establishment of cell-to-cell communication between the endometrium and the developing embryo is the most important step in successful mammalian pregnancy. Close interaction between the uterine luminal epithelium and trophoblast cells requires triggering timely molecular dialog for successful maternal recognition of pregnancy, embryo implantation, and placenta development. Quite recently, extracellular vesicles (EVs) carrying unique molecular cargo emerged as evolutionarily conserved mediators of cell-to-cell communication during early pregnancy. To date, the presence of EVs at the embryo-maternal interface has been demonstrated in numerous mammals, including domestic livestock, such as pigs. However, few studies have focused on revealing the mechanism of EV-mediated crosstalk between developing early embryos and receptive endometrium. Over the past years, it has appeared that understanding the role of EVs in mammalian reproduction can substantially improve our understanding of the biological challenges of successful reproductive performance. This review describes current knowledge of EVs, specifically in relation to the peri-implantation period in pigs, characterized by common features of embryo implantation and high embryonic mortality in mammals.

Early steps of embryo implantation are regulated by exchange of extracellular vesicles between the embryo and the endometrium.

In early pregnancy, as the embryo arrives in the uterus, intensive communication between the embryo and uterus begins. Hundreds of molecules are known to be involved, but despite numerous findings, full understanding of the complexity of the embryo-maternal dialog remains elusive. Recently, extracellular vesicles, nanoparticles able to transfer functionally active cargo between cells, have emerged as important players in cell-cell communication, and as such, they have gained great attention over the past decade also in reproductive biology. Here, we use a domestic animal model (Sus scrofa) with an epitheliochorial, superficial type of placentation because of its advantage in studding uterine luminal fluid extracellular vesicles. We show that during early pregnancy, the uterine lumen is abundant with extracellular vesicles that carry a plethora of miRNAs able to target genes involved in embryonic and organismal development. These extracellular vesicles, upon the delivery to primary trophoblast cells, affect genes governing development as well as cell-to-cell signaling and interactions, consequently having an impact on trophoblast cell proliferation, migration, and invasion. We conclude that the exchange of a unique population of extracellular vesicles and their molecular cargo at the maternal-embryo interface is the key to the success of embryo implantation and pregnancy.

miR-26a-5p and miR-125b-5p affect trophoblast genes and cell functions important during early pregnancy†.

The most critical stage of pregnancy is embryo implantation, which relies on the synchronized developmental capacity of the embryo and uterine receptivity to implantation. In early pregnancy, conceptus and uterus release several factors enabling successful implantation and placentation. Molecules involved in embryo-maternal crosstalk include, but are not limited to, hormones, growth factors, and cytokines. The discovery of microRNAs (small non-coding RNAs regulating gene expression) has revolutionized our understanding of many biological processes, including pregnancy. To date, numerous miRNAs have been detected in different species during pregnancy, both at the endometrial and embryonic sites. Thus, microRNAs are considered important regulators of early pregnancy events. Here, we report miR-26a-5p and miR-125b-5p effects on human and pig trophoblast cell function. Both microRNAs change the level of several genes and proteins important for proper embryo development. Moreover, miR-26a-5p stimulates porcine trophoblast proliferation and has a negative impact on its affinity to laminin. However, miR-125b-5p decreases porcine trophoblast cell migration. Our studies suggest that miR-26a-5p and miR-125b-5p can affect early pregnancy functions by regulating genes and processes important for proper conceptuses' development and progression through the implantation process.