Postdoctoral Research Scientist Columbia University Medical Center New York, New York, United States
Abstract: Incurable aging-related neurodegenerative diseases are a growing public health crisis. The ability to generate substantial quantities of disease-pertinent neuronal types, with and without predisposing mutations, holds great promise for probing disease mechanisms and developing therapies. However, current protocols yield neurons that fail to mature in vitro and stall at an embryonic identity. We understand how to make neurons, but what controls maturation? Could it be RNA metabolism? The mammalian nervous system employs alternative splicing (AS) at distinct developmental stages to massively expand transcriptomic diversity and protein function. The function of these programs is poorly understood, but presumably of importance since the content and timing of splicing switches are deeply conserved. Here, we show that a major bottleneck towards maturation of mouse and human stem cell-derived neurons is the inability to activate sequential programs of alternative splicing switches, affecting hundreds of genes. Through systematic characterization, we identify master splicing factors that control distinct AS programs during different phases of maturation. Critically, we manipulate developmental AS master regulators in mouse and human neurons to demonstrate that maturation can be distinctly advanced and accelerated through activation of stalled alternative splicing programs. Of note, our strategy yields cells with mature electrophysiology profiles on a shorter timescales, and generates neurons of mouse and human origin that express endogenous levels of mature tau isoforms within seven days in culture. Overall, this undertaking explores a novel function for alternative splicing during neurodevelopment, improves understanding of mechanisms that control maturation of neurons, and provides a refined stem cell-based model for studying disease, particularly tauopathies. Moreover, this technology has important applications for the exploration of aging biology and will be broadly useful to the scientific community for modeling neurodegenerative diseases and drug discovery.
Funding Source: This work is funded by the following: New York Stem Cell Foundation NIH
