Liong Stella, Lappas Martha
Mercy Perinatal Research Centre, Mercy Hospital for Women, Heidelberg, Vic., Australia.
Obstetrics, Nutrition and Endocrinology Group, Department of Obstetrics and Gynaecology, University of Melbourne, Melbourne, Vic., Australia.
Am J Reprod Immunol. 2015 Jul;74(1):62-76. doi: 10.1111/aji.12366. Epub 2015 Feb 4.
Sterile inflammation through activation of cytokine receptor signalling pathways and viral or bacterial infection via activation of Toll-like receptors (TLRs) induces a cascade of events that leads to myometrial contractions and spontaneous preterm delivery. In non-pregnant tissues, heme oxygenase-1 (HO-1) is thought to play a central role in regulating the inflammatory response. Thus, the aims of this study were to determine the effect of human term labour on HO-1 expression in human myometrium and to investigate the role of HO-1 in myometrial primary cells in response to cytokine- and TLR ligand-induced inflammation.
Localization and expression of HO-1 protein in human myometrial tissues were determined using IHC. Western blot analysis and qRT-PCR were also used to determine HO-1 protein and gene expression, respectively, in human myometrium. siRNA knock-down of HO-1 in myometrial primary cells was used to determine its role in response to inflammatory stimuli.
HO-1 gene expression and protein expression were increased in term labouring myometrium compared with non-labouring myometrium. Bacterial flagellin (TLR5 ligand), viral dsRNA analogue polyinosinic polycytidylic acid (poly(I:C)) (TLR3 ligand) and pro-inflammatory cytokines IL-1β and TNF-α induced pro-inflammatory cytokine (IL-6 and IL-8) mRNA expression and release in myometrial cells. IL-1β also induced COX-2 mRNA expression and prostaglandin release. HO-1 siRNA knock-down significantly decreased the expression and secretion of these prolabour mediators. Additionally, flagellin, poly(I:C), IL-1β, and TNF-α-induced NF-κB transcriptional activity were suppressed in HO-1-deficient myometrial cells.
Collectively, these findings in myometrium indicate HO-1 expression is increased with labour and exerts pro-inflammatory effects via NF-κB during cytokine- and TLR ligand-induced inflammation.
通过细胞因子受体信号通路激活引发的无菌性炎症以及通过Toll样受体（TLR）激活导致的病毒或细菌感染，会引发一系列事件，进而导致子宫肌层收缩和自发性早产。在非妊娠组织中，血红素加氧酶-1（HO-1）被认为在调节炎症反应中起核心作用。因此，本研究的目的是确定足月分娩对人子宫肌层中HO-1表达的影响，并研究HO-1在子宫肌层原代细胞中对细胞因子和TLR配体诱导的炎症反应中的作用。
采用免疫组织化学法确定HO-1蛋白在人子宫肌层组织中的定位和表达。蛋白质印迹分析和定量逆转录聚合酶链反应（qRT-PCR）也分别用于确定人子宫肌层中HO-1蛋白和基因的表达。利用小干扰RNA（siRNA）敲低子宫肌层原代细胞中的HO-1，以确定其在对炎症刺激反应中的作用。
与未分娩的子宫肌层相比，足月分娩的子宫肌层中HO-1基因表达和蛋白表达增加。细菌鞭毛蛋白（TLR5配体）、病毒双链RNA类似物聚肌苷酸胞苷酸（poly(I:C)）（TLR3配体）以及促炎细胞因子白细胞介素-1β（IL-1β）和肿瘤坏死因子-α（TNF-α）可诱导子宫肌层细胞中促炎细胞因子（IL-6和IL-8）的mRNA表达和释放。IL-1β还可诱导环氧合酶-2（COX-2）mRNA表达和前列腺素释放。HO-1 siRNA敲低显著降低了这些促分娩介质的表达和分泌。此外，在缺乏HO-1的子宫肌层细胞中，鞭毛蛋白、poly(I:C)、IL-1β和TNF-α诱导的核因子κB（NF-κB）转录活性受到抑制。
总体而言，这些在子宫肌层中的研究结果表明，HO-1表达随分娩增加，并在细胞因子和TLR配体诱导的炎症过程中通过NF-κB发挥促炎作用。
