Bayesian modeling to infer mechanisms of GWAS hypertension genes in rats

 描述(申请人提供)：高血压是影响数百万美国人的心脏病和中风的主要危险因素。全基因组关联研究已经提名了大量在人类高血压中起重要作用的基因。其中许多基因在很大程度上是未知的，这使得即使在细胞和动物模型系统中对它们的影响的研究也变得复杂。我们提出了一种新的方法，通过将这些基因放在致敏啮齿动物系统Dahl盐敏感(SS)大鼠的基因-基因相互作用的背景下来确定它们的功能，Dahl盐敏感(SS)大鼠是一种公认的高血压啮齿动物模型。我们将通过定义一种已知在盐敏感型高血压中具有重要功能的单细胞类型的分子网络来降低复杂性，即肾外髓髓质粗升支(MTAL)的上皮Na+转运细胞。我们将SS来源的原代培养的mTAL细胞暴露于一组九种刺激物以诱导转录变化。暴露后将定期收集样本，并测量其转录本。这些时间进程数据将使用一种新的贝叶斯图形方法进行分析，这将创建一个依赖时间的基因-基因相互作用网络。这个网络将被用来预测SS基因组敲除的影响。这些预测将使用原代培养的mTAL进行验证，这些mTAL来自四只以SS为背景的GWAS提名的基因敲除大鼠。基因敲除对网络的影响将被用来预测基因敲除大鼠的表型，这将在这些动物模型中进行测试。我们的方法建立的网络将为GWAS提名的基因提供背景信息，并将极大地促进GWAS提名的基因座转化为可测试和有用的动物模型，从而推动盐敏感型高血压的遗传学研究。

 DESCRIPTION (provided by applicant): Hypertension is a major risk factor for heart disease and stroke that affects millions of Americans. Genome- wide association studies (GWAS) have nominated a large number of genes as important in human hypertension. Many of these genes are largely unknown, complicating study of their effects even in cell and animal model systems. We propose a novel approach whereby the function of these genes may be determined by placing them into the context of gene-gene interactions in a sensitized rodent system, the Dahl salt- sensitive (SS) rat, a well-established rodent model of hypertension. We will reduce complexity by defining the molecular network of a single cell type known to be of functional importance in salt-sensitive forms of hypertension, the epithelial Na+ transporting cells of the medullary thick ascending limb (mTAL) of the renal outer medulla. We will expose SS-derived primary cultured mTAL cells to a panel of nine stimuli to induce transcriptional changes. Samples will be collected at regular intervals after exposure and their transcriptomes will be measured. These time-course data will be analyzed using a novel Bayesian graphical approach which will create a time-dependent gene-gene interaction network. This network will be used to make predictions about the effect of knockouts from the SS genome. These predications will be tested using primary cultured mTALs from four GWAS-nominated knockout rats on the SS background. The effects of the knockouts on the networks will be used to predict phenotypes for the knockout rats, which will be tested in these animal models. The network generated by our method will provide context for GWAS-nominated genes and will greatly improve the conversion of GWAS-nominated loci into testable and useful animal models, thereby advancing the study of the genetics of salt-sensitive hypertension.