Graduate Program of Medical Science, McMaster University, Hamilton, Ontario, Canada.
Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada.
Mol Hum Reprod. 2020 May 15;26(5):353-365. doi: 10.1093/molehr/gaaa018.
The human placental barrier facilitates many key functions during pregnancy, most notably the exchange of all substances between the mother and fetus. However, preclinical models of the placental barrier often lacked the multiple cell layers, syncytialization of the trophoblast cells and the low oxygen levels that are present within the body. Therefore, we aimed to design and develop an in vitro model of the placental barrier that would reinstate these factors and enable improved investigations of barrier function. BeWo placental trophoblastic cells and human umbilical vein endothelial cells were co-cultured on contralateral sides of an extracellular matrix-coated transwell insert to establish a multilayered barrier. Epidermal growth factor and forskolin led to significantly increased multi-nucleation of the BeWo cell layer and increased biochemical markers of syncytial fusion, for example syncytin-1 and hCGβ. Our in vitro placental barrier possessed size-specific permeability, with 4000-Da molecules experiencing greater transport and a lower apparent permeability coefficient than 70 000-Da molecules. We further demonstrated that the BeWo layer had greater resistance to smaller molecules compared to the endothelial layer. Chronic, physiologically low oxygen exposure (3-8%) increased the expression of hypoxia-inducible factor 1α and syncytin-1, further increased multi-nucleation of the BeWo cell layer and decreased barrier permeability only against smaller molecules (457 Da/4000 Da). In conclusion, we built a novel in vitro co-culture model of the placental barrier that possessed size-specific permeability and could function under physiologically low oxygen levels. Importantly, this will enable future researchers to better study the maternal-fetal transport of nutrients and drugs during pregnancy.
胎盘屏障在妊娠期间促进许多关键功能，尤其是在母体和胎儿之间交换所有物质。然而，胎盘屏障的临床前模型通常缺乏多层细胞层、滋养层细胞的融合以及体内存在的低氧水平。因此，我们旨在设计和开发一种胎盘屏障的体外模型，该模型将恢复这些因素，并能够改进对屏障功能的研究。将绒毛膜滋养层细胞和人脐静脉内皮细胞共培养在细胞外基质包被的 Transwell 插入物的相对侧，以建立多层屏障。表皮生长因子和 forskolin 导致 BeWo 细胞层的多核化显著增加，并增加了融合的生化标志物，例如 syncytin-1 和 hCGβ。我们的体外胎盘屏障具有特定大小的通透性，4000-Da 分子的转运量更大，表观渗透系数低于 70000-Da 分子。我们进一步表明，与内皮层相比，BeWo 层对小分子具有更大的抵抗力。慢性、生理低氧暴露（3-8%）增加了缺氧诱导因子 1α 和 syncytin-1 的表达，进一步增加了 BeWo 细胞层的多核化，并仅降低了小分子（457 Da/4000 Da）的屏障通透性。总之，我们构建了一种新型的胎盘屏障体外共培养模型，该模型具有特定大小的通透性，并可在生理低氧水平下发挥功能。重要的是，这将使未来的研究人员能够更好地研究妊娠期间母体-胎儿营养物质和药物的转运。
