TIMOTHY M LAVAUTE
$985,026
University of Pennsylvania
Pennsylvania
National Institute of Neurological Disorders and Stroke (NINDS)
Epitranscriptomics, analogous to the epigenetic code formed by DNA and histone modifications, is the study of more than 170 chemically distinct types of RNA modifications, which modulate nearly all aspects of RNA metabolism, such as splicing, translocation, decay, stability, and translation. The recent profound success of COVID19 mRNA vaccines utilizing the pseudo-uridine modification highlights the translational potential of epitranscriptomics. Emerging evidence suggests diverse roles and mechanisms of dynamic RNA modifications in the mammalian nervous system and the association of epitranscriptomic dysregulations with developmental, neurological, psychiatric, and degenerative brain disorders. The majority of recent epitranscriptomic studies used cultured immortalized cell lines and the physiological functions of various RNA modifications remain largely unexplored. Recent technical advances in human induced pluripotent stem cell (iPSC)-derived brain organoids and genome editing open doors to investigate epitranscriptomic regulation in human brain development processes and associated brain disorders. The overarching goal of this research program is to investigate roles and mechanisms of epitranscriptomic regulation in the development and function of the mammalian nervous system, and pathological consequences of disrupting these processes, using both mouse and human iPSC-derived 2D and 3D brain organoid models. There are three interrelated projects designed to test innovative hypotheses and generate foundational data for the field. In Project 1, we will focus on the development of the hypothalamus, an understudied brain region that regulates many key physiological functions, such as sleep, reproduction, and feeding, through its distinct nuclei. Based on our preliminary finding of adult-onset obesity of mice with defective m6A signaling, we will test the hypothesis that m6A signaling regulates the fate specification of neural stem cells in the arcuate nucleus for generating feeding-related neurons both in mice and human arcuate organoids. In Project 2, we will use novel sequencing technology to reveal the landscape of locally translated transcripts at synapses and investigate the role of m6A signaling in regulating activity-dependent local translation of these transcripts at synapses in the mouse hippocampus and human hippocampal organoids. In Project 3, we will focus on several risk genes associated with microcephaly that encode writer proteins for diverse epitranscriptomic modifications beyond m6A. We will generate isogenic iPSC lines and genetically modified animal models to test the functional roles and mechanisms of these RNA modifications in cortical neurogenesis. Together, we will use several orthogonal approaches to investigate functional roles and mechanisms of neuroepitranscriptomics in regulating the mammalian nervous system and its causal roles in mediating some forms of developmental pathology. The research program will also provide a platform to train the next generation of scientists from diverse backgrounds at different career stages.