In humans and higher primates, fetal trophoblasts gain access to the lumens of dilated uterine capillaries and migrate along endothelium against the flow of blood eventually remodeling spiral arteries. Our general hypothesis is that migration of trophoblasts within uterine blood vessels is regulated by blood flow-derived shear stress. New data now show that trophoblasts migrate against flow when cultured on top of confluent uterine endothelial cells. To account for these observations, two, not mutually exclusive, mechanisms are proposed. First, we suggest that shear stress causes an asymmetric distribution of immobilized chemokines or adhesion molecules on endothelial cells that generates a haptotactic gradient directing trophoblast migration against flow. Second, we suggest that interaction of trophoblasts with immobilized chemokines and/or adhesion molecules on endothelial cells results in trophoblast activation causing trophoblasts to respond to shear stress by migrating against flow.
Four aims will allow us to distinguish these mechanisms and characterize the features that define the shear stress-dependent migratory phenotype. First we will use videomicroscopy to characterize the effect of different levels of shear stress on the directional migration of trophoblasts on uterine endothelial cells.
Aim 2 uses confocal microscopy to study the role of chemokines and endothelial adhesion molecules in shear stress-mediated trophoblast migration. We will also use migration checkerboard assays to determine whether chemokine- or adhesion molecule-induced trophoblast migration is haptotactic, chemotactic or chemokinetic.
Aim 3 determines the effect of shear stress and trophoblast-endothelial interaction on induction of a migratory trophoblast phenotype. We will use confocal microscopy to characterize the leading edge/trailing edge distribution of CCR5, beta1 integrin, and cytoskeletal elements in trophoblasts exposed to different levels of shear stress in the presence of endothelial cells. Expression of these proteins will be quantiated by laser scanning cytometry, immunoblotting, and quantitative RT-PCR analysis. Function-blocking antibodies will identify the role of trophoblast adhesion molecules and chemokine receptors in flow-induced migration on endothelium.
Aim 4 will use quantitative laser scanning cytometry to examine the expression of chemokine receptors, chemokines, and adhesion molecules in intravascular trophoblasts and endothelial cells in serial sections of uterine tissue.
| Kumar, Priyadarsini; Thirkill, Twanda L; Ji, Jennifer et al. (2015) Differential Effects of Sodium Butyrate and Lithium Chloride on Rhesus Monkey Trophoblast Differentiation. PLoS One 10:e0135089 |
| Kumar, Priyadarsina; Lindberg, Louise; Thirkill, Twanda L et al. (2012) The MUC1 extracellular domain subunit is found in nuclear speckles and associates with spliceosomes. PLoS One 7:e42712 |
| Cao, Tim C; Thirkill, Twanda L; Wells, Mark et al. (2008) Trophoblasts and shear stress induce an asymmetric distribution of icam-1 in uterine endothelial cells. Am J Reprod Immunol 59:167-81 |
| Thirkill, Twanda L; Cao, Tim; Stout, Michael et al. (2007) MUC1 is involved in trophoblast transendothelial migration. Biochim Biophys Acta 1773:1007-14 |
| Vandevoort, Catherine A; Thirkill, Twanda L; Douglas, Gordon C (2007) Blastocyst-derived trophoblast stem cells from the rhesus monkey. Stem Cells Dev 16:779-88 |
| Thirkill, Twanda L; Vedagiri, Hemamalini; Douglas, Gordon C (2006) Macaque trophoblast migration toward RANTES is inhibited by cigarette smoke-conditioned medium. Toxicol Sci 91:557-67 |
| Soghomonians, Arlen; Barakat, Abdul I; Thirkill, Twanda L et al. (2005) Trophoblast migration under flow is regulated by endothelial cells. Biol Reprod 73:14-9 |
| Thirkill, Twanda L; Lowe, Kimberly; Vedagiri, Hemamalini et al. (2005) Macaque trophoblast migration is regulated by RANTES. Exp Cell Res 305:355-64 |
| Soghomonians, Arlen; Thirkill, Twanda L; Mariano, Natalie F et al. (2004) Effect of aqueous tobacco smoke extract and shear stress on PECAM-1 expression and cell motility in human uterine endothelial cells. Toxicol Sci 81:408-18 |
