Obesity, diabetes, and accompanying lipid and blood pressure dysregulation?collectively termed ?cardiometabolic disease? (CMD)?is a major contributor to cardiovascular disease. Despite long-standing data implicating small non-coding RNAs in CMD, less is known in regards to long non-coding RNAs (lncRNAs). Animal studies have recently suggested a role for lncRNAs in lipid homeostasis, fat thermogenesis and myocardial remodeling, each critical to CMD. While animal studies may heighten a suspicion for lncRNAs in CMD, studies in human tissue are imperative to establish their role. Studies focused on lncRNA expression in tissues central to CMD in humans are crucial to understand novel aspects of the molecular physiology of CMD and its downstream impact on cardiovascular health. Brown adipose tissue (BAT), central in energy expenditure regulation and metabolism, is inversely correlated with body-mass index (BMI). Preliminary data from our group using human adipocytes from BAT and white adipose tissue (WAT) has identified specific lncRNAs that are differentially expressed and altered in proportion with increasing BMI and diabetes. Currently, in silico determination of lncRNA-mRNA regulation remains problematic (due to lack of curated resources), and large-scale validation in accessible tissue (e.g., plasma) from populations at-risk for CMD and downstream cardiovascular risk is lacking. Therefore, understanding the role of lncRNAs in humans must (1) be performed in human tissues relevant to CMD; (2) identify coordinate changes between lncRNA and mRNA expression (as possible targets of lncRNA regulation); (3) include association studies between lncRNAs and CMD phenotypes to enable future larger mechanistic studies in CMD. Here, we hypothesize that lncRNAs differentially expressed in BAT vs. WAT or relevant in adipogenesis will be (1) associated with expression of genes central to CMD pathogenesis and (2) dynamically expressed in plasma as a function of cardiometabolic perturbations known to impact CMD and cardiovascular disease (e.g., bariatric surgery, insulin resistance). To address this central hypothesis, we bring together our preliminary human adipose tissue RNA-seq data with several very unique resources: (1) ongoing WAT, BAT, and plasma collection from prospective resources at the NIH Clinical Center and our institution; (2) an NIH-funded study of individuals pre-/post-bariatric surgery in which we have performed non-coding RNA quantification (U54HL112311) and have preliminary data establishing large changes in lncRNAs with weight loss; (3) population-wide data (n=3100) including CMD, mRNA measurements, and available RNA for lncRNA analyses. This application is based on preliminary data providing candidate lncRNAs that are differentially expressed in metabolically active fat. It is bolstered by active collaborations and samples previously collected from NIH/NHLBI sponsored studies, as well as innovative bioinformatics methods to identify possible lncRNA gene targets. All data will be made publically available and created as a shared resource.
One of the most transformative discoveries is that select classes of RNAs do not directly code for genes but can still regulate a wide range of biological systems. One of the most recently described types is termed long noncoding RNAs. Although vastly greater in number than coding RNAs, current research can only examine them in cell culture models due to differences between species. In such studies, they have been linked to metabolic diseases that occur because of obesity, but whether this occurs in man is unknown. By studying hundreds to thousands of these long noncoding RNAs from fat tissue and the circulation of thousands of well- characterized people, we will gain great insight into their biological relevance as well as therapeutic and diagnostic potential.
