CSE和CBS对胎盘血管生成因子和抗血管生成因子的调节作用及其与子痫前期发生和发展的关系

It is known that excess amount of antiangiogenic factors released by placenta is critical to dysfunction of endothelia in preeclampsia (PE). The mechanisms underlying regulation of angiogenic factors and antiangiogenic factors remain largely unknown. We have found that human placenta expressed the enzymes, which are involved in H2S synthesis and metabolism of homoysteine, cystathionine ? synthase (CBS) and cystathionine ? lyase(CSE). In PE placenta, CSE and CBS were downregulated compared with normal placenta. At meantime, the rate of H2S production was reduced and the level of homocysteine was increased. The expression of CSE and CBS was positively correlated to VEGFA, whereas inversely correlated to sFlt1. We are going to explore the effect of H2S and homocysteine on production of angiogenic and antiangiogenic factors in placental cells and the molecular mechanisms involved in these processes. We will investigate whether blockage of these two enzymes or knockdown of these two enzymes in placenta result in preeclampsia as well as accumulation of homocysteine and higher levels of antiangiogenic factors in peripheral circulation in an animal model. We will also observe whether ischemia of placenta results in downregualtion of CSE and CBS, reduced H2S production and accumulation of homocysteine in vivo and in vitro. We will also construct adenovirus containing CSE and CBS gene and infect the placenta with this virus in an animal model of PE, thereby resulting in overexpression of CSE and CBS in placenta, and then observe blood pressure, protein content in urine and the levels of angiogenic and antiangiogenic factors in plasma, thereby determining whether overexpression of CSE and CBS ameliorate PE. The present project will clarity the role of placental CSE and CBS in the pathogenesis of PE.

胎盘产生过量抗血管生成因子和较少血管生成因子是导致子痫前期血管内皮损伤的重要原因。我们以往研究表明胎盘表达与H2S和同型半胱氨酸代谢有关的酶- - 胱硫醚β合成酶（CBS）和胱硫醚γ合酶（CSE），CSE和CBS在子痫前期胎盘表达降低，同时H2S生成减少及同型半胱氨酸升高，这两种酶与血管生成因子VEGF呈正相关、与抗血管生成因子sFlt1呈负相关，提示它们参与胎盘血管生成因子和抗血管生成因子的调节。我们将进一步研究由这两种酶产生的H2S、同型半胱氨酸对胎盘细胞血管生成因子和抗血管生成因子的调节及其分子机制；胎盘这两种酶表达减少是否导致子痫前期的表现、血中抗血管生成因子增多而血管生成因子减少以及同型半胱氨酸的蓄积；胎盘缺血是否可导致这两种酶表达的减少、H2S生成减少、同型半胱氨酸的蓄积；过表达这两种酶是否可改善子痫前期的表现等，以阐明这两种酶在子痫前期发病中的作用及其可能的分子机制。

H2S是近年来新发现的一种气体信号分子，主要通过CBS、CSE和3-MST产生。本项目的目的是研究胎盘H2S生成酶的表达异常与子痫前期的发生和发展的关系及其可能机制。我们观察到，PE胎盘组织中CBS和CSE的表达量显著降低且PE胎盘组织的H2S生成率低于正常胎盘。目前已知胎盘促血管生成因子和抗血管生成因子的失衡是导致子痫前期高血压和肾损害的重要原因，我们发现CBS和CSE的表达量与血管生成因子VEGF呈正相关而与抗血管生成因子sFlt-1呈负相关。在离体培养的胎盘组织外植体和原代滋养层细胞培养上，我们观察到H2S可促进VEGF生成而抑制sFlt-1的产生，还可影响绒毛外滋养细胞的迁移和侵袭功能。对H2S作用机制的研究结果表明，H2S对VEGF 和sFlt-1的调控作用部分与调控VEGFA 和sFlt-1mRNA的稳定性有关，且这种作用是通过调节了一系列mirRNA而实现的。我们还发现H2S抑制sFlt1的生成还与其抑制蛋白脱落作用相关酶ADAM10/17表达进而抑制sFlt-1 从Flt-1的脱落。我们的研究提示了胎盘H2S可影响滋养细胞的功能并在血管因子和抗血管因子生成调节中起关键作用，H2S生成异常将导致滋养细胞侵入子宫能力降低，还可导致胎盘抗血管因子和血管因子生成的失衡，进而促进了子痫前期的发生和发展。此外，我们还研究了H2S的生成酶CBS和CSE在其他妊娠组织如胎膜和子宫肌等中的作用，结果显示，内源性H2S维持胎膜中前列腺素代谢酶（PGDH）起关键作用，子宫组织中内源性H2S还在维持子宫静息中起重要作用,胎膜和子宫肌组织中H2S生成量减少参与了分娩启动和早产的发生。