University of Maryland, Animal and Avian Sciences, College Park, MD 20742, USA.
Placenta. 2013 Jul;34(7):536-43. doi: 10.1016/j.placenta.2013.03.016. Epub 2013 Apr 28.
Preeclampsia and other placental pathologies are characterized by a lack of spiral artery remodeling associated with insufficient invasion by extravillous trophoblast cells (EVT). Because trophoblast invasion occurs in early pregnancy when access to human placental tissue is limited, there is a need for model systems for the study of trophoblast differentiation and invasion. Human embryonic stem cells (hESC) treated with BMP4- differentiate to trophoblast, and express HLA-G, a marker of EVT. The goals of the present study were to further characterize the HLA-G(+) cells derived from BMP4-treated hESC, and determine their suitability as a model.
HESC were treated with BMP4 under 4% or 20% oxygen and tested in Matrigel invasion chambers. Both BMP4-treated hESC and primary human placental cells were separated into HLA-G(+) and HLA-G(-)/TACSTD2(+) populations with immunomagnetic beads and expression profiles analyzed by microarray.
There was a 10-fold increase in invasion when hESC were BMP4-treated. There was also an independent, stimulatory effect of oxygen on this process. Invasive cells expressed trophoblast marker KRT7, and the majority were also HLA-G(+). Gene expression profiles revealed that HLA-G(+), BMP4-treated hESC were similar to, but distinct from, HLA-G(+) cells isolated from first trimester placentas. Whereas HLA-G(+) and HLA-G(-) cells from first trimester placentas had highly divergent gene expression profiles, HLA-G(+) and HLA-G(-) cells from BMP4-treated hESC had somewhat similar profiles, and both expressed genes characteristic of early trophoblast development.
We conclude that hESC treated with BMP4 provide a model for studying transition to the EVT lineage.
子痫前期和其他胎盘病变的特征是螺旋动脉重塑不足，伴绒毛外滋养细胞（EVT）浸润不足。由于滋养细胞浸润发生在妊娠早期，此时获取人胎盘组织受限，因此需要建立滋养细胞分化和浸润的模型系统。用 BMP4 处理的人胚胎干细胞（hESC）可分化为滋养细胞，并表达 EVT 的标志物 HLA-G。本研究的目的是进一步描述 BMP4 处理的 hESC 衍生的 HLA-G+细胞，并确定其作为模型的适用性。
hESC 在 4%或 20%氧条件下用 BMP4 处理，并在 Matrigel 侵袭小室中进行测试。用免疫磁珠将 BMP4 处理的 hESC 和原代人胎盘细胞分离为 HLA-G+和 HLA-G-/TACSTD2+细胞，并通过微阵列分析其表达谱。
BMP4 处理可使 hESC 的侵袭增加 10 倍，且氧对该过程有独立的刺激作用。侵袭细胞表达滋养细胞标志物 KRT7，且大多数细胞也表达 HLA-G。基因表达谱显示，HLA-G+、BMP4 处理的 hESC 与从早孕期胎盘分离的 HLA-G+细胞相似，但又不同。尽管早孕期胎盘的 HLA-G+和 HLA-G-细胞的基因表达谱有很大差异，但 HLA-G+和 HLA-G-细胞的基因表达谱有一定的相似性，两者均表达了早期滋养细胞发育特征的基因。
我们的结论是，用 BMP4 处理的 hESC 为研究向 EVT 谱系的转变提供了模型。
