Jiang K, Chen Y, Jarvis J N
Department of Pediatrics, Pediatric Rheumatology Research, Basic Sciences Ed Bldg #235A, University of Oklahoma College of Medicine, Oklahoma City, OK 73104, USA.
Placenta. 2007 May-Jun;28(5-6):538-42. doi: 10.1016/j.placenta.2006.06.013. Epub 2006 Aug 10.
Infection of the maternal vaginal tract is one of the single most important antecedents of premature labor. We have hypothesized that the abundant local synthesis of pro-inflammatory cytokines that occurs during infection may disrupt the delicate "immunological cross-talk" that must occur between maternal and fetal tissues in order to carry pregnancy to term. These experiments were undertaken as part of a larger study directed at testing that hypothesis. We prepared primary cultures of human trophoblasts from term placentas. Cell cultures were stimulated with conditioned medium from resting, PHA or LPS-activated peripheral blood mononuclear cells (PBMC). Medium with LPS or PHA at the same concentration as that used to stimulate the PBMC was used as an additional control. Lysates were subjected to western blotting for activated forms of the mitogen-activated protein kinases (MAPK), Stat1, and Stat3. Western blotting showed phosphorylation of the Jun kinase (JNK), p38, and Erk1/Erk2 MAPK in trophoblasts incubated with conditioned medium from LPS or PHA-activated PBMC but not from medium from resting PBMC, or with PHA or LPS alone. Phosphorylation could be detected as early as 5 min and was still observable by 10 min, the latest time point tested. Similarly, Stat1 and Stat3 phosphorylation was observed within 10 min of exposure to conditioned medium and was still observable 10 min after exposure. Immunohistochemistry also demonstrated nuclear translocation of both Stat1 and Stat3 after stimulation of trophoblasts with medium from activated PBMC. These findings are compatible with the hypothesis that immunologic balance at the maternal-fetal interface is maintained by ongoing "cross-talk" between the fetus (and fetally-derived tissues) and the maternal immune system. Infection of the maternal vaginal tract may disrupt this delicate immunologic balance, initiating inflammatory events that ultimately result in preterm labor.
母体阴道感染是早产最重要的单一诱因之一。我们推测，感染期间发生的促炎细胞因子大量局部合成可能会破坏母体和胎儿组织之间为使妊娠足月而必须发生的微妙“免疫串扰”。这些实验是作为一项旨在验证该假设的更大规模研究的一部分而进行的。我们从足月胎盘制备了人滋养层细胞的原代培养物。用来自静息、PHA或LPS激活的外周血单个核细胞（PBMC）的条件培养基刺激细胞培养物。使用与用于刺激PBMC相同浓度的LPS或PHA培养基作为额外对照。裂解物进行免疫印迹，检测丝裂原活化蛋白激酶（MAPK）、Stat1和Stat3的活化形式。免疫印迹显示，与来自LPS或PHA激活的PBMC的条件培养基孵育的滋养层细胞中，Jun激酶（JNK）、p38和Erk1/Erk2 MAPK发生磷酸化，但与来自静息PBMC的培养基或单独的PHA或LPS孵育的细胞中未发生磷酸化。磷酸化最早可在5分钟检测到，在测试的最晚时间点10分钟时仍可观察到。同样，在暴露于条件培养基后10分钟内观察到Stat1和Stat3磷酸化，暴露后10分钟仍可观察到。免疫组织化学也显示，用来自活化PBMC的培养基刺激滋养层细胞后，Stat1和Stat3均发生核转位。这些发现与以下假设一致，即胎儿（和胎儿来源的组织）与母体免疫系统之间持续的“串扰”维持了母胎界面的免疫平衡。母体阴道感染可能会破坏这种微妙的免疫平衡，引发炎症事件，最终导致早产。
