Static state of epithelial mesenchymal transition in fetal membrane cells: a novel inflammatory pathway to parturition

摘要 胎膜（绒毛膜）提供结构框架，并执行机械和保护功能。 在怀孕期间发挥作用。p38丝裂原活化蛋白激酶（MAPK）介导的进行性 衰老（老化的机制）发生在胎膜中。它与胎儿生长有关， 由于宫腔内氧化应激（OS）增加，足月时加速。胎儿衰老 组织引起炎症，可以促进劳动;因此，膜在怀孕中起着关键作用， 分娩在整个妊娠期间，细胞膜通过修复自身来维持体内平衡， 脱落，基质降解。这种重塑过程会产生间隙和微骨折。在细胞 尽管如此，尚不清楚膜的多能性羊膜上皮细胞和间充质细胞如何修复细胞膜， 受损网站由于重构对于维持膜稳态和防止不良反应是必不可少的， 怀孕的结果，了解这个过程是至关重要的。我们已经确定羊膜损伤 上皮细胞（AEC）迫使AEC增殖和细胞迁移以重建损伤部位，这是正常的 生理反应初步数据表明，OS和p38 MAPK介导的衰老引起上皮细胞的衰老， 间充质转化（EMT），并通过增加TGF β的产生来防止组织重塑。我们也 证实TGF β具有双重功能：1）通过p38 MAPK的自磷酸化诱导衰老 和2）诱导EMT转录因子以促进细胞和机械膜破裂。这些 孕酮（P4）可逆转上述作用。我们假设平衡的组织重塑维持了胎儿 膜稳态在怀孕期间，但TGF β增加，由于压倒性的OS在任期或响应 早产时感染和炎症（TNF α）引起p38 MAPK介导的不可逆状态， 衰老和EMT可促进膜损伤。此外，我们假设，在 在妊娠期间，TGF β介导的转换由孕酮（P4）平衡。我们将使用以下方法来检验我们的假设： 2个具体目标： 目的1-确定LPS（感染）和TNF α（炎症）是否可引起TGF β-TAB1-p38 MAPK 信号通路，导致AEC中的EMT。 目的2-研究P4在LPS和TNF α介导的TGF β产生中的调节作用， 减少EMT TGF β-P4在正常条件下对膜稳态的维持作用及其机制 感染/炎症破坏促进EMT可能为早产提供新的途径 由膜破裂介导。

ABSTRACT Fetal membranes (amniochorion) provide the structural framework and perform mechanical and protective functions during pregnancy. A progressive p38 mitogen-activated protein kinase (MAPK)-mediated senescence (mechanism of aging) occurs in fetal membranes. It is correlated with fetal growth and is accelerated at term due to increased oxidative stress (OS) in the intrauterine cavity. Senescence of fetal tissues causes inflammation that can promote labor; thus, membranes play a critical role in pregnancy and parturition. Throughout gestation, membranes maintain homeostasis by repairing themselves when cells are shed and the matrix is degraded. This remodeling process creates gaps and microfractures. At the cellular level, it remains unclear how the membranes' pluripotent amnion epithelial and mesenchymal cells repair the damaged sites. Since remodeling is essential for maintaining membrane homeostasis and preventing adverse pregnancy outcomes, understanding this process is critical. We have determined that injury to amnion epithelial cells (AEC) forces AEC proliferation and cell migration to rebuild injured sites, which is a normal physiologic response. Pilot data suggest that OS- and p38 MAPK-mediated senescence cause epithelial mesenchymal transition (EMT) and prevent tissue remodeling through increased production of TGFβ. We also determined that TGFβ plays dual functions: 1) induction of senescence by autophosphorylation of p38MAPK and 2) induction of EMT transcription factors to facilitate cellular and mechanical membrane disruption. These effects were reversed by progesterone (P4). We hypothesize that balanced tissue remodeling maintains fetal membrane homeostasis during pregnancy, but TGFβ increase due to overwhelming OS at term or in response to infection and inflammation (TNFα) at preterm causes an irreversible state of p38MAPK-mediated senescence and EMT that can promote membrane damage. Additionally, we hypothesize that during pregnancy, TGFβ-mediated transitions are balanced by progesterone (P4). We will test our hypotheses using 2 specific aims: Aim 1—To determine if LPS (infection) and TNFα (inflammation) can cause TGFβ -TAB1-p38MAPK signaling pathways, leading to EMT in AEC. Aim 2—To determine the regulatory role of P4 in LPS and TNFα-mediated TGFβ production and its ability to reduce EMT. Maintenance of membrane homeostasis by TGFβ-P4 during normal conditions and its disruption by infection/inflammation promoting EMT may provide a novel pathway to preterm parturition mediated by membrane disruption.