Grant: CIHR Fellowship

Lipid-lipid phase separation is a physical phenomenon characterized by molecules de-mixing into distinct lipid phases. This process is known to drive the formation of membrane-less compartments in cells that concentrate biochemical reactions. Increasing evidence points to the involvement of aberrant phase separation in neurodegenerative disorders through excessive protein aggregation. Rett syndrome (RTT) is a postnatal progressive neurodevelopmental disease associated with severe mental retardation that primarily affects females. The majority of the clinical cases have been traced to mutations of MECP2, a multi-talented protein that acts as a repressor or an activator of transcription. However, the mechanism underlying the complex role of MECP2 in cellular physiology and RTT particularly remains enigmatic. The Jaenisch laboratory has recently demonstrated that MECP2 can form phase-separated condensates in murine cells. On this basis, I aim to expand the role of phase separation in biological function and disease-causing malfunction of MECP2 to the human system. I will leverage the experimental paradigm established in the Jaenisch lab and use human embryonic stem (ES) cells to generate normal and RTT neurons in both two-dimensional (2D) and three-dimensional (3D) culture systems, and explore the molecular properties of phase separation in these human models. The human ES cells will be engineered to carry relevant disease-causing mutations in the MECP2 gene. The goal of this project is to advance the mechanistic understanding of MECP2's function and pave the way for new therapeutic approaches for RTT.