Snail-HDAC1/2介导孕期尼古丁暴露致胎儿骨软骨发育迟缓的机制研究

Epidemiological investigations confirmed that uterus-fetus system exposed to smoke during pregnancy would cause skeletal growth retardation in fetuses，resulting in reduction in height of newborns. Among a multitude of chemicals arising from cigarette smoking, nicotine is one of the leading candidates for causing small newborns and delayed skeletal growth in fetuses. In our previous study, we observed that following prenatal nicotine exposure resulted in skeletal growth retardation, the mRNA and protein expression levels of extracellular matrix genes (aggrecan, Col2A1) in fetal growth plate were all remarkably reduced, suggesting that nicotine can acts on growth plate chondrocytes to inhibit matrix synthesis. However, the possible mechanism of suppression of aggrecan, and Col2A1 expressions in fetal growth plate by prenatal nicotine exposure remains unclear. According to our recent studies, we propose that nicotine can act on fetal growth plate chondrocyte to suppress matrix synthesis via increasing the expression of Snail which recruits HDAC1/2 to decrease histone acetylation in the promoter of aggrecan and Col2A1, leading to skeletal growth retardation. The present works will be helpful to clarify delayed chondrogenesis caused by prenatal nicotine exposure. The aim of this study is to evaluated the risks of intrauterine delayed chondrogenesis and skeletal growyh by prenatal nicotine exposure which including maternal subjective and passive smoking during pregnancy.

流行病研究揭示：孕期吸烟可以引起胎儿骨软骨发育迟缓，表现为胎儿身长明显较正常短小。作为烟草的主要活性成分之一，尼古丁可通过胎盘对胎儿骨骼发育产生不良影响。我们前期研究发现，尼古丁孕期暴露可导致胎鼠骨软骨发育迟缓，胎生长板软骨基质合成不足，基质表型基因aggrecan和Col2A1表达下降，但其具体分子机制尚不清楚。结合我们近期研究结果，本项目拟利用动物和细胞实验，探讨“孕期尼古丁暴露→宫内胎生长板软骨细胞Snail高表达并招募HDAC1/2→aggrecan及Col2A1启动子区组蛋白乙酰化水平降低→胎生长板软骨基质合成障碍→胎儿骨软骨发育迟缓”之间的内在联系，阐明孕期尼古丁暴露所致胎儿骨软骨发育迟缓的宫内分子作用机制及干预靶标。本研究为评估因主动或被动吸烟引起的孕期尼古丁暴露导致胚胎骨软骨发育迟缓的风险，指导优生优育和提高人口质量，具有重要的理论和现实意义。

流行病研究揭示：孕期吸烟可以引起胎儿骨软骨发育迟缓，表现为胎儿骨干明显较正常短小。作为烟草的主要活性成分之一，尼古丁可通过胎盘对胎儿骨骼发育产生不良影响。我们前期研究结果发现，尼古丁孕期暴露可导致胎鼠骨软骨发育迟缓，胎生长板软骨基质合成不足，基质表型基因aggrecan和Col2A1表达下降，但其具体分子机制尚不清楚。结合我们近期研究结果，本项目拟利用细胞实验，探讨“孕期尼古丁暴露致宫内胎生长板软骨细胞Snail高表达并招募HDAC1/2，aggrecan及Col2A1启动子区组蛋白乙酰化水平降低，进一步引起胎生长板软骨基质合成障碍，最终致胎儿骨软骨发育迟缓”之间的内在联系，阐明孕期尼古丁暴露所致胎儿骨软骨发育迟缓的宫内分子作用机制及干预靶标。不同浓度尼古丁（0， 0.1，1，10，和100 μM尼古丁）作用胎鼠生长板软骨细胞7天，尼古丁在各个浓度作用下能明显的抑制生长板软骨细胞Ⅱ型胶原和的aggrecan的表达，并且具有浓度依赖性。RT-PCR检测示，尼古丁明显增加了细胞Snai的表达，上调了HDAC1/2的表达，且具有浓度依赖性。尼古丁可显著降低aggrecan和Col2A1组蛋白乙酰化水平。给予HDAC1/2特异性抑制剂后，尼古丁对细胞aggrecan和Col2A1表达的抑制作用明显减弱，Snail的表达也较尼古丁组明显减少，aggrecan和Col2A1组蛋白乙酰化水平也明显增加。尼古丁作用于胎鼠生长板软骨细胞，可上调细胞Snail表达并招募HDAC1/2，进一步降低aggrecan和Col2A1组蛋白乙酰化水平，导致软骨细胞外基质Ⅱ型胶原合成不足。本研究为评估因主动或被动吸烟引起的孕期尼古丁暴露导致胚胎骨软骨发育迟缓的风险，指导优生优育和提高人口生存质量，具有重要的理论和现实意义。