Age-dependent regenerative mechanisms in the brain

There is an unmet need for repair following injury in humans, particularly in the brain where endogenous stem cell activity is minimal. An understanding of neural progenitor diversity and flexibility in their fate choices is crucial for understanding how complex organs like the brain are generated or undergo repair. The neonatal mouse cerebellum is a powerful model system to uncover regenerative responses due to its high regenerative potential.   We have previously shown that the cerebellum can recover from the loss of at least two types of neurons via distinct regenerative mechanisms (Wojcinski, 2017; Bayin, 2018; Bayin, 2021). In one case, a subpopulation of the nestin-expressing progenitors (NEPs) that normally generate astroglia undergoes adaptive reprogramming and replenishes the lost neurons. However, the molecular and cellular mechanisms that regulate neonatal cerebellar development and adaptive reprogramming of NEPs upon injury are unknown.   Interestingly, the regenerative potential of the cerebellum decreases once development ends, despite the presence of NEP-like cells in the adult cerebellum that respond to cerebellar injury by increasing their numbers. However, neuron production is blocked. We hypothesize that the lack of regeneration is due to a lack of pro-regenerative developmental signals in the adult brain in addition to epigenetic silencing of stem cell differentiation programs and inhibitory cellular mechanisms as development is completed.  

Our lab is interested in answering two overarching questions:  
1)    What are the cellular and molecular mechanisms that enable regeneration in the neonates and inhibit in the adult?
2)    Can we facilitate regeneration in the brain?  

This project involves interdisciplinary approaches ranging from in vivo mouse genetics, in vitro modelling and stem cell assays, and single cell and other genomics technologies. Our system allows us to interrogate fundamental stem cell biology questions in a systematic manner and unravel the molecular mechanisms that govern neural stem cells during development, homeostasis and upon injury. The student taking on this project benefit from our multidisciplinary approach and participate in our collaborative work locally and internationally.