Role of steroid hormones in the maintenance of focal adhesions in bovine oviductal epithelial cells.

The oviduct, the organ of the female reproductive system where fertilization and early embryonic development occur, provides an optimal environment for the final maturation of oocytes, storage, and sperm capacitation and transport of gametes and embryos. During the estrous cycle, the oviduct is affected by ovarian sex hormones, resulting in changes aimed at maintaining an appropriate microenvironment. Normal cell migration is tightly regulated, its role being essential for the development and maintenance of organ and tissue functions as well as for regeneration following injury. Due to their involvement in focal contact formations, focal adhesion kinase (PTK2) and paxillin (PXN) are key proteins in the study of cell migration and adhesion. The objective of this work was to compare the expression of PTK2 and PXN in oviductal cells along the estrous cycle and to determine if their expression is regulated by the presence of 17-ß estradiol (E2) and/or progesterone (P4). No transcripts of PTK2 or of PXN were detected in cells corresponding to the luteal phase. Additionally, hormonal stimulation experiments on bovine oviductal cell cultures (BOECs) were carried out, where P4 inhibited the expression of both genes. Migration assays demonstrated that P4 reduced BOECs migration capacity. P4 treatment also reduced cell adhesion, while E2 increased the number of adhered cells. In conclusion, the presence of E2 and P4 regulates the expression of genes involved in the formation of focal contacts and modifies the migration and adhesion of BOECs. Understanding the effect of steroid hormones on BOECs is critical to grasp the impact of steroid control on oviductal function and its contribution to establishing successful pregnancies.

A long-term in vitro culture of bovine epithelial cells on collagen rafts.

In the present work, we established and characterized a 3D functional polarized primary bovine oviduct epithelial cells (BOECs) culture on free-floating type I collagen hydrogels (rafts) at an air-liquid interface (ALI). Intercellular junctions, ultrastructural cellular morphology and the expression of the OVGP1 closely recapitulated those of the in vivo epithelium lining. These morphological and physiological epithelial cell features were maintained under standard DMEM/F12 with 10% foetal bovine serum culture medium for at least 28 days of ALI culture. The versatility of the BOECs raft cultures should allow testing of toxicity compounds, in vitro evaluation of physiological or pathological oviductal states, and the study of epithelial-mesenchymal interactions that are critical for the maintenance of oviductal homeostasis.

Expression of bone morphogenetic protein receptors in bovine oviductal epithelial cells: Evidence of autocrine BMP signaling.

Members of the transforming growth factor beta (TGF-ß) family, including bone morphogenetic proteins (BMPs), are expressed in the epithelial cells of the mammalian oviduct. These signaling molecules play important roles in development and tissue homeostasis; however, little is known about their function in the mammalian oviduct. In the present study, RT-qPCR was used to analyze the mRNA abundance of BMP type I (BMPR1A, BMPR1B, ACVR1) and type II receptors (BMPR2, ACVR2A, ACVR2B) in the bovine oviduct epithelial cells (BOEC) isolated from ampulla and isthmus at both the follicular (FP) and the luteal (LP) phase of the estrous cycle. Results indicate that mRNAs for all the BMP receptors studied are expressed in the BOEC. Significant mRNA abundance differences were observed for both BMPR1B and ACVR2B when comparing both the ampulla and isthmus regions with the greater abundance at the isthmus. When both FP and LP samples were compared, ACVR2B mRNA showed greater abundance during the LP, with significant differences in the isthmus region. These variations highlight differences between the isthmus and ampulla regions of the oviduct. By means of wound healing assays on BOEC primary cultures, exogenous recombinant human BMP5 induced a significant increase in wound healing at 24h. The observed changes at the mRNA abundance of components of the signaling pathway and the BMP5 effect on oviductal epithelial cells suggest a possible autocrine role for the BMP pathway that could affect epithelial cell functions necessary for normal physiology and reproductive success in BOEC homeostasis.