Division of Basic Science and Translational Research, Department of Obstetrics & Gynecology, The University of Texas Medical Branch at Galveston, 301 University Blvd., Galveston, TX 77555-1062, United States of America.
Division of Basic Science and Translational Research, Department of Obstetrics & Gynecology, The University of Texas Medical Branch at Galveston, 301 University Blvd., Galveston, TX 77555-1062, United States of America; Department of Biochemistry and Molecular Biology, College of Medicine, University of the Philippines Manila, 547 Pedro Gil St., Manila 1000, Philippines.
Life Sci. 2022 Oct 15;307:120867. doi: 10.1016/j.lfs.2022.120867. Epub 2022 Aug 6.
Environmental exposure to toxicants is a major risk factor for spontaneous preterm birth (PTB, <37 weeks). Toxicants and drugs administered to patients are metabolized primarily by the cytochrome P450 (CYP450) system. Along with the adult and fetal liver, the placenta, a critical feto-maternal interface organ, expresses CYP450 enzymes that metabolize these xenobiotics. However, the contribution of the fetal membranes, another tissue of the feto-maternal interface, to the expression of CYP450 enzymes and the detoxification of xenobiotics remains unknown.
This study characterized CYP450 expression and determined the functional activity of CYP450 enzymes in fetal membranes.
RNA sequencing (RNA-Seq) of placental and fetal membrane tissues and cells was done. Differential expressions of CYP450 genes were compared and validated via reverse transcription-quantitative polymerase chain reaction (RT-qPCR) between the two tissues. The functional activity of major CYP450 enzymes was determined using a fluorophore-based enzymatic assay in the presence and absence of their corresponding inhibitors.
With the exception of genes that regulate cholesterol metabolism, the expression profile of CYP450 genes was similar between placental and fetal membranes tissues/cells. RT-qPCR analysis confirmed these findings with significant levels of mRNA for major CYP450 genes being detectable in amnion epithelial cells (AECs) and chorion trophoblasts cells (CTCs). Biochemical analyses revealed significant CYP450 enzymatic activities that were sensitive to specific inhibitors for both AECs and CTCs, suggesting that the genes were expressed as functional enzymes.
This is the first study to determine global expression of CYP450 enzymes in fetal membranes which may play a role in xenobiotic metabolism during pregnancy. Given that many women are exposed to environmental toxins or require medications during pregnancy, a better understanding of their role in metabolism is required to develop safer therapeutics and prevent adverse outcomes.
环境暴露于有毒物质是自发性早产（PTB，<37 周）的主要危险因素。给予患者的毒物和药物主要通过细胞色素 P450（CYP450）系统代谢。胎盘是胎儿与母体的重要界面器官，除了成人和胎儿的肝脏外，还表达代谢这些外源性物质的 CYP450 酶。然而，胎儿膜作为胎儿与母体界面的另一种组织，对 CYP450 酶的表达和外源性物质的解毒作用的贡献尚不清楚。
本研究旨在表征胎儿膜中 CYP450 的表达，并确定 CYP450 酶的功能活性。
对胎盘和胎儿膜组织和细胞进行 RNA 测序（RNA-Seq）。通过两种组织之间的逆转录定量聚合酶链反应（RT-qPCR）比较和验证 CYP450 基因的差异表达。在存在和不存在其相应抑制剂的情况下，使用基于荧光的酶促测定法确定主要 CYP450 酶的功能活性。
除了调节胆固醇代谢的基因外，胎盘和胎儿膜组织/细胞的 CYP450 基因表达谱相似。RT-qPCR 分析证实了这一发现，在羊膜上皮细胞（AEC）和绒毛滋养细胞（CTC）中可检测到主要 CYP450 基因的 mRNA 水平显著。生化分析显示 AEC 和 CTC 均存在对特定抑制剂敏感的显著 CYP450 酶活性，表明这些基因表达为功能性酶。
这是首次在胎儿膜中确定 CYP450 酶的全基因表达的研究，这些酶可能在妊娠期间对外源性物质的代谢中发挥作用。鉴于许多女性在怀孕期间暴露于环境毒素或需要药物治疗，因此需要更好地了解它们在代谢中的作用，以开发更安全的治疗方法并预防不良后果。
