Epitranscriptomics in human obesity and type 2 diabetes

PROJECT SUMMARY Dysfunction of multiple metabolic cells contribute to the pathophysiology of the two major pathological states, obesity and type 2 diabetes, which have a huge economic burden worldwide. Identifying the etiology of the two linked pathological states continues to be an area of intense research with a focus on identifying new

regulatory pathways within tissues that impact metabolic function and cause dysfunction. There is a continuing need to develop a systems biology framework that integrates real patient data to inform signaling within cells and crosstalk between tissues to enable identification of potential new targets for effective therapy.

An emerging area of significance in human obesity and type 2 diabetes (T2D) is epigenetics that has primarily focused on DNA methylation and protein modifications. A missing link in this epigenetic framework is the modification(s) in mRNA and chromatin-associated regulatory RNAs (carRNAs) that have been shown to

contribute to gene expression regulation at both posttranscriptional and transcriptional levels. Current data indicate altered expression of various regulators in metabolic tissues (e.g. human islets, adipose, liver, skeletal muscle) in obesity and type 2 diabetes; however, the significance of these alterations and the impact on mRNA

and protein expression in real human tissues is virtually unknown. Consistent with the requirement of a RC2 mechanism, we will develop a comprehensive database of functionally important RNA modifications in selected human tissues. We seek to interrogate alterations in the modifications of RNA, specifically, the two most

important modifications, N6-adenosine methylation (m6A) and pseudouridylation in key metabolic cell types that are relevant for type 2 diabetes and obesity. In this proposal, we will: 1) Interrogate the mRNA and chromatin- associated RNA modifications, m6A-sequencing and BID-ψ-sequencing at base resolution with stoichiometry

information in key metabolic tissues from patients with T2D and obesity; 2) Perform m6A and ψ QTL studies in tissues from patients with T2D and obesity and validate the functional relevance of key mRNA and chromatin- associated RNA modifications in in vitro studies; 3) Interrogate comprehensive transcription and enhancer

activity using ATAC-seq in the metabolic tissues from patients with T2D and obesity; 4) Perform eQTL studies using transcriptional activity data obtained from KAS-seq and RNA modification results on carRNAs in T2D and obese tissues, and perform validation in in vitro studies; and 5) Develop a large-scale resource database on

mRNA and chromatin-associated RNA modifications and transcription activity with correlation of common genomic features for the larger scientific community. The success of this project will lay ground for the broader community to take advantage of these data and our analyses for future basic and translational investigations

and therapeutic developments.