Energy is stored in adipocytes as a large uniocular lipid droplet, which can be broken down into fatty acids (FAs) and released into the circulation when needed. This specialised lipid storage and breakdown requires dynamic organisation of metabolic enzymes and cofactors around the large lipid droplet for metabolic homeostasis. In obesity, the adipocyte dysfunctions, resulting in high spontaneous release of FAs. This chronic release and elevation of systemic FAs is a major driver of systemic insulin resistance, type 2 diabetes and other cardiometabolic diseases. I postulate that long non-coding RNAs (lncRNAs) interact with the metabolic machinery within the adipocyte to organize cell- and stimulation-specific interactomes, channelling substrate flux within the cell. Adipocytes express over 4000 lncRNAs, many of which are unique to humans and this cell type. However, whether these lncRNAs contribute to the adipocyte’s specialised lipid metabolism in health and disease is not understood. This proposed research aims to address this question. I have already developed key methodologies to study lncRNAs in human adipocytes, including a novel technique called TROOPS that identifies specific lncRNA-interacting proteins. Leveraging an extensive bank of white adipose tissue biopsies from uniquely characterized patients, I will identify disease-regulated lncRNAs and test how they function in human adipocytes. I will use gene editing techniques and lipid/metabolomics analysis to define the role of these lncRNAs in lipid storage and FA release. Furthermore, I will use protein-lncRNA complex purification combined with advanced microscopy techniques to reveal how lncRNAs can sequester protein complexes into phase-separated organelles and organize adipocyte lipid metabolism. These insights will provide a paradigm shift in understanding how lncRNAs enable the adipocyte to perform specialized functions and new generalizable findings for how lncRNAs contribute to cell function.

Type 2 diabetes (T2D) is a multifactorial disease affecting over 450 million people in Europe alone, amounting to the burden of life-threatening diseases and worsening quality of life. Skeletal muscle is affected early in T2D and contributes to the fast decline of whole-body glucose homeostasis, which is called insulin resistance. Interestingly, even when isolated from the body and cultured in a laboratory in non-diabetogenic conditions, the skeletal muscle cells do not lose the characteristics of the donor, i.e., the cells remain insulin resistant, indicating the existence of a cell-autonomous mechanism that retains the metabolic memory across generations of cells. Nonetheless, such a mechanism remains elusive. Accumulating evidence suggests a potential role of histone post-translational modifications as essential vectors of inheritable information, but it is still a matter of intense debate. In this project, to address this question and understand the pathology of T2D, we will trace a comprehensive genome-wide map of histone post-translational modifications induced by T2D in human primary skeletal muscle cells and investigate whether these histone marks can store and transmit information about the metabolic phenotype from the donor to the next generation of cells. Targeted studies using pharmacological and genetic interventions will then address the role of histone modifying enzymes in metabolic memory transmission. The outcomes could lead to a novel understanding of a broader system of cellular memory storage and transmission. By characterizing the disturbances caused by diabetes in the epigenome using state-of-the-art techniques and multidisciplinary approaches, we could pave the way for innovative clinical interventions addressing a critical global health challenge.