赖氨酰氧化酶在子痫前期发生发展中的作用及其机制研究

Dysfunction of trophoblast cells is the main pathological basis of preeclampsia. Thus, the key to interpret the pathogenesis of preeclampsia is to identify the regulating mechanisms of the biological behaviours in trophoblast cells. It has been reported that lysyl oxidase (LOX) plays an important role in regulating the growth and metastasis of tumors. However, the roles of LOX in trophoblast cells with similar biological behaviours to tumor cells are not clear. Our preliminary results showed that 1) LOX mainly locates in the cytoplasm of trophoblast cells in placenta; 2) the proliferation and migration as well as invasion was declined in trophoblast cells over-expressed LOX; 3) the expression levels of LOX were higher in placenta with preeclampsia than those of placenta from normal pregnancy;4) LOX expression levels were highly positively correlated with the expression levels of hypoxia inducible factors (HIFs) in the placenta with preeclampsia. The preliminary results suggested that LOX involves in the occurrence and development of preeclampsia by regulating the biological behaviours of tropholbast cells. Thus, on the basis of our preliminary results, this project is designed to figure out the biological functions of LOX in primary culturing trophoblast cells, reveal the molecular mechanisms, verify the contribution of LOX to preeclampsia in mouse model, and make clear the regulating roles of HIFs on LOX. This study is going to settle theoretical basis for revealing the pathogenesis of preeclampsia and is promising to provide new strategies for the prevention and therapy of preeclampsia.

滋养细胞功能不足是子痫前期的主要病理学基础。明确滋养细胞生物学行为的调节机制是阐明子痫前期发病分子机理的关键。已有研究表明赖氨酰氧化酶(lysyl oxidase, LOX)具有调节肿瘤生长及转移的作用，但LOX在与肿瘤细胞具有相似生物学行为的滋养细胞中的调控作用尚不明确。我们前期研究结果显示：LOX主要定位于胎盘的滋养细胞；过表达LOX后，滋养细胞系HTR8/SVneo的增殖、迁移侵袭能力下降；在子痫前期胎盘中LOX的表达水平升高且与缺氧诱导因子表达水平正相关。前期研究结果提示，LOX可能通过调控滋养细胞的生物学行为参与子痫前期的发生发展。本项目将在前期工作的基础上进一步研究LOX对原代滋养细胞的调控作用及其分子机制，通过体内实验探讨LOX过表达与子痫前期发生发展的关系，并解析缺氧诱导因子对LOX的调节功能。本研究将为揭示子痫前期的发病机理奠定理论基础，并有望为子痫前期的防治提供新线索。

子痫前期是母婴发病与死亡的主要因素，它是妊娠期特发的一个重要疾病，发生率高达6-8%。孕早期滋养细胞侵袭功能受损被认为与子痫前期的发生相关，但是潜在的机制尚未明确。通过本项目的研究我们发现赖氨酰氧化酶家族成员LOX和LOXL2在子痫前期发生中起关键作用。我们的实验结果显示，LOX和LOXL2在子痫前期的胎盘组织中低表达；在滋养细胞中敲减LOX或者LOXL2后，滋养细胞的迁移侵袭功能减弱。我们进一步探讨了敲低LOX和LOXL2影响滋养细胞迁移侵袭功能的机制。结果表明，在LOX、LOXL2敲低的滋养细胞中，TGF-β1/Smad3信号通路被激活，从而诱导了胶原分子的表达。用Smad3抑制剂处理LOX、LOXL2敲低的滋养细胞，滋养细胞的迁移侵袭功能得到恢复，揭示了滋养细胞中TGF-β1/Smad3是LOX及LOXL2下游的重要通路。此外，进一步在临床样本中检测发现，子痫前期胎盘组织中胶原含量增加并且TGF-β1/Smad3被激活。综上所述，本项目的研究显示LOX及LOXL2下调表达会激活TGF-β1/Smad3/collagen信号通路，进而减弱滋养细胞的迁移侵袭功能，可能与子痫前期的发病相关。因此，我们的研究提示LOX, LOXL2以及 TGF-β1/Smad3/胶原信号通路有望成为子痫前期诊断和治疗的潜在靶点。