硫化氢通过抑制NLRP3炎性小体激活维持子宫静息的分子机制

It lacks effective clinical management approach to delay preterm labor. This fail is largely due to our ignorance of the fundamental mechanisms underlying uterine transformation from quiescent state into procontractile state during pregnancy. Our previous research suggests that uterine activation for labour is associated with inflammatory responses within uterine tissues, hydrogen sulfide (H2S), suppresses the uterine activation via inhibition NF-κB and proinflammatory cytokines in pregnant human myometrial cells. Our data indicate that H2S plays a critical role in the maintenance of uterine quiescence during pregnancy. However, the mechanism of H2S inhibiting uterine contraction through anti-inflammatory is still to be further discussed. Intrauterine local inflammatory response is closely related to the activation of innate immunity pattern recognition receptors, the expression levels of NLRP3 in human gestational tissues are higher and have significant negative correlation with H2S. NLRP3 inflammasome expressions were inhibited by NF-κB inhibitor. Therefore, we propose the hypothesis: H2S may suppresses the activation of NLRP3 inflammasome via inhibition of NF-κB, and maintain the quiescence of the uterus. Human pregnancy tissue, NLRP3 knockout mice are used to confirm the relationship between NLRP3 inflammasome and labor, and the role of NF-κB in the activation of NLRP3 inflammasome, cell experiments were used to clarify the mechanism of H2S suppresses the activation of NLRP3 inflammasome via inhibition of NF-κB. The study will help to furtherly clarity the mechanism of human parturition and provide new ideas for prevent preterm birth.

早产的发生未得到有效控制根本原因是分娩启动的机制尚未阐明。我们前期研究证实炎症在分娩启动中发挥重要作用，硫化氢（H2S）可通过抑制NF-κB和炎性因子维持子宫静息，但确切的机制还有待进一步探讨。临床研究证明宫内炎症反应与天然免疫模式识别受体的激活密切相关，我们发现在早产、足月产的妊娠组织中存在NLRP3炎性小体高表达,且与H2S的生成存在显著负相关，而NF-κB抑制剂可抑制NLRP3炎性小体的表达。因此我们提出课题假说：H2S可能通过调控NF-κB抑制NLRP3炎性小体的激活抑制炎症反应，维持子宫静息。我们利用人妊娠组织、基因敲除鼠明确NLRP3炎性小体参与分娩启动的作用，并阐明分娩启动中NF-κB是NLRP3炎性小体激活的关键调控因子；利用细胞实验明确H2S通过调控NF-κB抑制NLRP3炎性小体激活，维持子宫静息的机制。本项目将有助于阐明人类分娩启动的机制，为早产防治提供新思路。

早产的发生未得到有效控制根本原因是分娩启动的机制尚未阐明。我们前期证实分娩是一个炎症过程，宫内的局部炎症反应与NLRP3炎性小体的激活密切相关。硫化氢（H2S）可通过抑制炎症因子维持子宫静息，但确切的机制还有待进一步探讨。基于此.本项目以炎症触发子宫激活为切入点，探究NLRP3炎性小体的激活在分娩启动中的作用并找到调控其激活的关键因子：收集早产、足月临产、足月未临产人妊娠组织，早产、未临产、临产小鼠妊娠子宫肌、构建NLRP3基因敲除鼠、子宫平滑肌细胞转染siNLRP3。发现无论在人、动物妊娠组织上，还是体外细胞试验中，都证明NLRP3炎性小体的激活参与了分娩启动的过程。进一步探究分娩启动中NF-κB与NLRP3的相关性，结果发现NLRP3与Pp65之间存在显著正相关。在动物模型给与NF-κB抑制剂，结果证实NF-κB是调控NLRP3炎性小体激活的关键因子。.深入研究H2S是否通过抑制NLRP3炎性小体的激活维持子宫静息：人妊娠子宫肌组织、CSE基因敲除鼠和细胞水平上探究H2S抑制子宫激活与NLRP3之间的关系，结果发现，人妊娠子宫肌组织中，NLRP3的表达与H2S合成酶CBS和CSE成显著负相关。H2S供体NaSH可以延缓LPS诱导的小鼠早产，抑制子宫肌中NLRP3的激活。细胞实验中H2S可以抑制IL-1β诱导的炎症反应并抑制NLRP3炎性小体、收缩相关蛋白、TLR4、及NF-κB的活化。在人子宫平滑肌细胞上探究分娩启动中H2S调控NLRP3激活的机制，结果证实H2S可通过调控TLR4-NF-κB信号通路抑制NLRP3炎性小体的激活进而维持子宫静息，参与分娩启动的过程。.此外，我们还发现，在妊娠末期，TLR4可通过NF-κB/P38MAPK通路上调炎性因子和子宫收缩相关蛋白表达进而促进子宫激活。.本研究成果以期为揭示分娩启动的动因和机制提供新的思路，为临床早产的防治提供重要意义。