Lin28/Let-7信号通路对子宫腺肌病平滑肌细胞增殖和凋亡调控的机制研究

Adenomyosis (ADS) is an estrogen-dependent disease with unclear aetiology that has a tremendous impact on women’s well-being and health. There has no effective treatment of adenomyosis, its incidence is rising and the incident age gets younger that makes adenomyosis a formidable clinical problem. At present, in the understanding of the pathophysiology of adenomyosis, the functional disorder of the endometrial-myometria interface(EMI) results from abnormal proliferation of smooth muscle cells turns out to be of utmost importance. Our previous study assessed microRNAs(miRNAs) expression by microarray analysis in the EMI of women with versus without adenomyosis and identified forteen up-regulated and eight down-regulated miRNAs. Let-7 families,especially let-7a evidenced down-regulation and the expression of its negative regulation factor Lin28 was much higher than that of the control. Morever, 17β-estrodiol stimulation made the down-expression of let-7. Therefore,we propose that estrogen may induce dysfuctional contraction and abnormal structure of EMI smooth muscle by activating Lin28/ let-7 signaling, that plays a fundamental role in the clinical features of adenomyosis. Our research using microarray analysis, flow cytmetry and molecular biotechnology discover the pathogenesis of adenomyosis from a new sight and offer a new target for the prevention and treatment of uterine adenomyosis.

子宫腺肌病（ADS）是严重危害女性健康的雌激素依赖性疾病，发病率逐年增高且呈年轻化趋势；由于其病因机制不明、缺乏有效治疗方法，已成为临床亟待解决难题。目前认为ADS发病与子宫内膜-肌层交界区（EMI）平滑肌异常增殖所致的结构与功能紊乱密切相关。我们前期研究发现，ADS子宫EMI平滑肌细胞中存在多个micro-RNAs(miRNAs)表达差异，其中与细胞增殖凋亡密切相关的let-7表达下调尤为显著，其负性调控因子Lin28则呈持续高表达；而雌激素又能够使EMI平滑肌细胞let-7的表达持续下调。由此我们推测，雌激素通过激活Lin28/let-7通路，诱导EMI平滑肌细胞增殖与凋亡紊乱进而导致其结构与功能异常，是子宫腺肌病发病与临床表现的关键。本研究借助miRNA和mRNA表达谱芯片检测、分子生物学和流式细胞分析等技术，从一个崭新的视角探讨ADS发病机制并为临床寻求有效的靶向治疗提供依据。

子宫腺肌病（ADS）是严重危害妇女健康的雌激素依赖性疾病，病因机制不清，无有效治疗方法，发病率上升和年轻化趋势已使其成为临床亟待解决难题。目前认为ADS发病与子宫内膜-肌层交界区（EMI）平滑肌异常增殖所致的结构与功能紊乱密切相关。ADS子宫EMI平滑肌细胞中与细胞增殖凋亡密切相关的let-7表达下调尤为显著，其负性调控因子Lin28则呈持续高表达。此外，ADS发生发展与子宫内膜细胞侵袭能力增加有关。而且该过程与上皮间质转化（epithelial-mesenchymal transition，EMT）关系密切。. 本研究借助分子生物学、流式细胞分析和聚光共聚焦等技术阐明：（1）Lin28/let-7对ADS子宫EMI平滑肌增殖凋亡功能影响的信号传导通路；（2）雌激素介导的上皮-间质转化在ADS发生发展具有重要作用。结果发现：（1）EMI平滑肌中，Lin28B表达量高于Lin28A，腺肌病EMI中Lin28B的表达量显著增加，失去周期性调控； 腺肌病组中，Lin28A与Let-7a无相关性，只有Lin28B表达与Let-7a呈负相关；（2）雌激素受体阻断剂ICI 182,780可通过降低PI3K和AKT的表达，抑制PI3K/AKT信号通路促进腺肌病子宫EMI平滑肌细胞的凋亡；转染siRNA-Lin28B亦可抑制PI3K和AKT的表达，Lin28B缺失可通过上调let-7a来降低腺肌病EMI细胞的增殖能力。与ICI 182,780相比，siRNA-Lin28B抑制作用更加明显，Lin28/let-7通过PI3K/AKT信号通路调节腺肌病子宫EMI平滑肌细胞的凋亡；（3）局部黏着斑激酶（FAK）在ADS中表达升高，并伴随上皮间质转化相关分子改变，EMT相关转录因子Snail、Slug、Twist表达升高，EMT相关标志物E-cadherin、Cytokeratin的表达均低于对照组，Vimentin、N-cadherin的表达确异常升高，表明FAK通过上皮间质转化过程参与子宫腺肌病的发生发展；（4）抑制FAK表达，PI3K/AKT通路相关分子表达亦受抑制，子宫内膜细胞运动能力降低，EMT相关转录因子Snail、Slug、Twist表达均低于阴性对照组，EMT相关标志物E-cadherin、Cytokeratin的表达均高于阴性对照组，Vimentin、N-cadher