对FoxA1性别特异性结合介导肝脏炎症反应差异的全基因组研究

Liver inflammation is a male-predominant disease on both human and rodents, no matter what the cause is. To date neither sex hormone difference nor genome composition difference could soundly explain this kind of gender discrepancy. From our previous study, we found that in mouse liver, male-specific Transcription Factor Binding Sites (TFBS) were significantly enriched within nearby regions of immune response and inflammatory related genes, while transcription pioneer factor FoxA1 motif were found significantly enriched in these inflammatory gene nearby sites, indicating the intrinsic difference of liver epi-genome might be responsible for this sex-specific phenomenon. In this application, we proposed to do genome-wide FoxA1 ChIP-Seq on both sexes to extract sex-specific FoxA1 binding sites, with computational approach to extract nearby genes, annotate their function, and inspect their differential expression in a mouse hepatitis model. Also, we decide to apply siRNA to attenuate FoxA1 expression in the same model, to explore the following change on hepatitis gender disparity. We also try to locate key TFs following differential FoxA1 binding with motif-finding approach. To see if a link could be found between sex-specific regulation embraced at epi-genomic level and sex-specific response to liver inflammation, and illustrate its underlying mechanism.

多种起因的肝脏炎症疾病在人鼠等多个物种中均表现出显著的雄性相对雌性病情更重的现象,这种差异目前从性激素和传统基因组学角度尚不能良好解释。在前期工作中我们发现雄性特异的转录因子结合位点显著地富集在炎症反应相关基因附近，且转录前驱因子FoxA1的基序在雄性特异位点中显著出现，提示炎症反应的性别差异很可能由表观基因组水平的差异所决定，通过FoxA1的差异结合介导。本研究计划以FoxA1的ChIP-Seq实验发现并比较小鼠肝脏中FoxA1性别特异的结合位点，通过生物信息学方法找出受这类位点调控的基因，并与小鼠肝炎模型中差异表达的基因相印证；使用siRNA干扰模型中FoxA1的表达来观察FoxA1同炎症反应性别差异的关联，继而寻找由FoxA1引导的关键转录因子。从而将FoxA1的性别特异性结合引起的差异转录调控与肝炎性别差异联系起来，力图阐明造成该现象的内在原因，为转录调控研究及肝炎治疗提供新思路。

多种起因的肝脏炎症疾病在人鼠等多个物种中均表现出显著的雄性相对雌性病情更重的现象,这种差异目前从性激素和传统基因组学角度尚不能良好解释。在前期工作中我们发现雄性特异的转录因子结合位点显著地富集在炎症反应相关基因附近，且转录前驱因子FoxA1的基序（motif）在雄性特异结合位点中显著出现，提示炎症反应的性别差异很可能由表观基因组水平的差异所决定，通过FoxA1的差异结合介导。本研究中我们以FoxA1的ChIP-Seq实验发现并比较小鼠肝脏中FoxA1性别特异的结合位点，通过生物信息学方法找出受这类位点调控的基因，注释它们的功能并研究它们与炎症反应的关系。发现FoxA1在小鼠肝细胞基因组中的结合具有显著的性别差异，且雄性特异的FoxA1结合位点富集在一部分炎症反应相关基因附近（主要同急性期反应及补体通路相关），且调控了这类基因在炎症状态下的性别间差异表达。此外我们利用靶向FoxA1的CRISPR系统影响其体内水平(通过含sgRNA的腺病毒载体尾静脉注射)，成功使上述炎症相关基因在雄性中的表达下调。同时我们通过motif-finding和表达量相关性分析等手段寻找由FoxA1引导的关键转录因子，发现Creb1可能是一个潜在分子。本研究将FoxA1的性别特异性结合引起的差异转录调控与肝炎性别差异联系起来，为转录调控研究及肝炎治疗提供了新思路。