Pregnancy and Development Group, Mater Research Institute-University of Queensland, Translational Research Institute, Brisbane QLD, Australia.
Pregnancy and Development Group, Mater Research Institute-University of Queensland, Translational Research Institute, Brisbane QLD, Australia.
Placenta. 2021 May;108:64-72. doi: 10.1016/j.placenta.2021.03.013. Epub 2021 Mar 29.
The human placenta expresses multiple glucocorticoid receptor (GR) isoforms that may be partially regulated by the untranslated 5' exon 1 GR gene promoter region which consists of 9 different promoters and 13 splice variants. The objective of this study was to determine which GR exon 1 variants are expressed in the human placenta and relate these findings to GR mRNA and protein expression.
Placental extracts from pregnancies with or without the complication of maternal asthma and trophoblast cells exposed to an inflammatory challenge in vitro were examined using PCR and Western blot to measure GR exon 1 variants, GR splice variant mRNA and GR protein isoforms, respectively.
All 9 GR exon 1 variants were detectable in the human placenta and included GR exons 1A, 1B, 1C, 1D, 1E, 1F, 1H, 1I and 1J. In the presence of maternal asthma and a male fetus there was preferential expression of GR exon 1B, 1C, IF and 1J (KW-ANOVA, P < 0.05) which were positively correlated with GRα D3 protein isoform. In female placentae from pregnancies complicated by asthma there was no upregulation of any exon 1 variant (KW-ANOVA, P < 0.05). Exposure of BeWo trophoblast cell line to an inflammatory challenge, lipopolysaccharide, in vitro, resulted in preferential expression of GR exon 1B, 1D, 1E and 1H and associated with GRα-D1 protein upregulation.
The preferential expression of different GR exon 1 promoters drive the upregulation of GRα D isoforms and contribute to glucocorticoid resistance observed in male placentae of pregnancies complicated by asthma.
人类胎盘表达多种糖皮质激素受体 (GR) 异构体，这些异构体可能部分受未翻译的 5'外显子 1 GR 基因启动子区域调控，该区域由 9 个不同的启动子和 13 个剪接变体组成。本研究的目的是确定哪些 GR 外显子 1 变体在人胎盘中表达，并将这些发现与 GR mRNA 和蛋白表达相关联。
使用 PCR 和 Western blot 分别检测有无母体哮喘并发症的妊娠胎盘提取物和体外暴露于炎症挑战的滋养层细胞，以测量 GR 外显子 1 变体、GR 剪接变体 mRNA 和 GR 蛋白异构体。
所有 9 种 GR 外显子 1 变体均可在人胎盘中检测到，包括 GR 外显子 1A、1B、1C、1D、1E、1F、1H、1I 和 1J。在母体哮喘和男性胎儿存在的情况下，GR 外显子 1B、1C、IF 和 1J 的表达更为优先（KW-ANOVA，P<0.05），与 GRα D3 蛋白异构体呈正相关。在母体哮喘并发症的女性胎盘中，没有任何外显子 1 变体的上调（KW-ANOVA，P<0.05）。体外将 BeWo 滋养层细胞系暴露于炎症挑战物脂多糖后，导致 GR 外显子 1B、1D、1E 和 1H 的优先表达，并与 GRα-D1 蛋白的上调相关。
不同 GR 外显子 1 启动子的优先表达驱动 GRα D 异构体的上调，并导致哮喘并发症妊娠中男性胎盘中观察到的糖皮质激素抵抗。
