Generation and Use of Trophoblast Stem Cells and Uterine Myocytes to Study the Role of Connexins for Pregnancy and Labor.

Transgenic mouse models have demonstrated critical roles for gap junctions in establishing a successful pregnancy. To study the cellular and molecular mechanisms, the use of cell culture systems is essential to discriminate between the effects of different connexin isoforms expressed in individual cells or tissues of the developing conceptus or in maternal reproductive tissues. The generation and analysis of gene-deficient trophoblast stem cell lines from mice clearly revealed the functions of connexins in regulating placental development. This chapter focuses on the use of connexin gene-deficient trophoblast stem cell cultures to reveal the individual role of gap junctions in regulating trophoblast differentiation and proliferation in vitro under controlled conditions. In addition, cultures of primary uterine myocytes, isolated from mice or rats, allow studying the effects of mechanical stretch or ovarian hormones on regulating connexin expression, and thus, to model the molecular mechanisms of uterine growth and development during pregnancy. Here, we describe the derivation of primary uterine myocyte cultures and their use in in vitro stretch experiments to study the mechanisms of myometrial remodeling essential to accommodate the growing fetus throughout gestation.