Tracing transcriptomic changes to uncover unknown roles of TZDs

 描述（由申请人提供）：肥胖是由白色脂肪组织（WAT）中储存的脂肪形式的过量卡路里引起的，是代谢紊乱（包括2型糖尿病）的主要风险因素。人类中燃烧脂肪的棕色脂肪组织（BAT）的发现提出了一种令人兴奋的可能性，即BAT可能被靶向治疗肥胖和代谢疾病。噻唑烷二酮（TZD）可以将WAT转化为“棕色”状态，它们已被用作糖尿病的治疗药物，但由于严重的副作用，其临床应用受到限制。对TZD作用的分子理解将导致开发有效但风险较低的代谢疾病药物。在我们的初步研究中，我们观察到新生RNA（GROseq）中广泛的共转录剪接。我们发现TZDs调节共转录剪接以及剪接体基因的转录水平。有趣的是，具有改变的共转录剪接比率的基因与布朗宁效应和PPAR信号通路相关。基于这些观察，我们建议研究TZDs调控的选择性剪接，并确定与胰岛素敏感性的关联。此外，我们最近发现，TZDs重新分配Med1占用，一个亚基的调解人。有趣的是，Med23，介体的另一个亚基，调节选择性剪接。基于这些观察，我们的目标是研究介体再分布是否与选择性剪接有关。此外，我们进一步旨在通过整合新生RNA（GROseq）和稳态RNA（RNAseq）来研究RNA稳定性。不同剪接的同种型具有不同的半衰期。使用一种系统的方法来整合转录组学数据，我们将研究TZDs是否调节RNA稳定性。我们使用新生和稳态RNA的创新方法将通过充分利用转录组学景观来增强我们对TZD的理解。我们的研究的全面性将揭示以前未被认识的TZDs在调节选择性剪接和RNA稳定性的调节机制。我们的研究将引导我们识别出有效的、低风险的药物靶点，以治疗社会中普遍存在的代谢紊乱。

 DESCRIPTION (provided by applicant): Obesity, caused by excess calories stored as fat in white adipose tissue (WAT), is a major risk factor for metabolic disorders including type 2 diabetes. The discovery of fat-burning brown adipose tissue (BAT) in humans has raised the exciting possibility that BAT may be targeted to treat obesity and metabolic diseases. Thiazolidinediones (TZDs) can function to convert WAT into a "brown-like" state, and they have been used as a remedy for diabetes, but their clinical use has been limited because of serious side effects. A molecular understanding of TZD action will lead to the development of efficacious yet lower-risk drugs for metabolic disorders. In our preliminary studies, we observed widespread co-transcriptional splicing in nascent RNAs (GROseq). We found that TZDs regulate co-transcriptional splicing as well as the transcription levels of splicesomal genes. Interestingly, genes with altered co-transcriptional splicing ratios were associated with browning effect and PPAR signaling pathway. Based on these observations, we propose to study alternative splicing regulated by TZDs and determine the association with insulin sensitivity. Also, we recently found that TZDs re-distribute Med1 occupancy, a subunit of the Mediator. Interestingly, Med23, another subunit of the Mediator, regulates alternative splicing. Based on these observations, we aim to study if the mediator redistribution is associated with alternative splicing. Moreover, we further aim to study RNA stability by integrating nascent RNA (GROseq) and steady-state RNA (RNAseq). Isoforms spliced differently have different half-lives. Using a systematic way to integrate transcriptomic data we will investigate if TZDs regulate RNA stability. Our innovative approach to use nascent and steady-state RNAs will enhance our understanding of TZDs by fully exploiting the transcriptomic landscapes. The comprehensive nature of our study will reveal previously unrecognized regulatory mechanisms of TZDs in regulating alternative splicing and RNA stability. Our study will lead us to the identification of efficacious, low-risk drug targets fr the metabolic disorders that pervade society.