Regulation of stem cell quiescence and proliferation
Project ID: NMH00053
Department: Gurdon Institute
Supervisor: Prof. Andrea Brand
Stem cell populations in tissues as varied as blood, gut, and brain, spend much of their time in a mitotically dormant, quiescent, state. A key point of regulation is the decision between quiescence and proliferation. The ability to reactivate neural stem cells in situ raises the prospect of potential future therapies for brain repair after damage or neurodegenerative disease. Understanding the molecular basis for stem cell reactivation is an essential first step in this quest.
In Drosophila, quiescent neural stem cells are easily identifiable and amenable to genetic manipulation, making them a powerful model with which to study the transition between quiescence and proliferation. These stem cells exit quiescence in response to a nutrition-dependent signal from the fat body, a tissue that plays a key role in the regulation of metabolism and growth. The proposed project will combine cutting edge genetic and molecular approaches with advanced imaging techniques to study the reactivation of Drosophila neural stem cells in vivo. This will make it possible to deduce the sequence of events from the level of the organism, to the tissue, the cell, and finally the genome. The questions that will be addressed are:
1) How do environmental signals influence neural stem cell behaviour? What are these signals and how are they received by the stem cell niche and transmitted to neural stem cells?
2) What are the transcriptional and epigenetic changes in neural stem cells in the transition from quiescence to proliferation?
3) How conserved are the molecular mechanisms regulating neural stem cell reactivation in Drosophila and mammals?
Otsuki L and Brand AH (2018) Cell cycle heterogeneity directs the timing of neural stem cell activation from quiescence. Science. 360(6384):99-102. doi: 10.1126/science.aan8795.
Cheetham SW and Brand AH (2018) RNA-DamID reveals cell-type-specific binding of roX RNAs at chromatin-entry sites. Nature Struct Mol Biol. 2018 25(1):109-114. doi: 10.1038/s41594-017-0006-4.
Spéder P and Brand AH (2018) Systemic and local cues drive neural stem cell niche remodelling during neurogenesis in Drosophila. eLife. 7: e30413. doi: 10.7554/eLife.30413.
Marshall OJ and Brand AH (2018) Chromatin state changes during neural development revealed by in vivo cell-type specific profiling. Nature Comm. 8(1):2271. doi: 10.1038/s41467-017-02385-4.
We established a collaboration with Dr Fiona Doetsch, Biozentrum, University of Basel, Switzerland, to investigate the parallels between stem cell quiescence in the brains of Drosophila and adult mice. My lab has developed a powerful approach for whole genome profiling in specific cell- and tissue-types in vivo (Targeted DamID). This technique enables genome-wide profiling of transcription factor binding and chromatin protein binding sites in small numbers of cells in the intact organism, without cell isolation. We have modified this technology for use in mouse embryonic stem cells and in vivo, in the developing mouse brain. Professor Sally Temple, Scientific Director of the Neural Stem Cell Institute, New York, USA, has expressed an interest in collaborating with us to interrogate the regulation of quiescent human neural stem cells. Professor Temple's research spans from basic to translational research with a view to developing treatments for damage to the nervous system.
Cheetham SW, Gruhn WH, van den Ameele J, Krautz R, Southall TD, Kobayashi T, Surani MA, Brand AH (2018) Targeted DamID reveals differential binding of mammalian pluripotency factors. Development. Sep 5. pii: dev.170209. doi: 10.1242/dev.170209. [Epub ahead of print]
Marshall O.J., Southall T.D., Cheetham S.W. and Brand A.H. (2016). Cell-type-specific profiling of protein-DNA interactions without cell isolation using targeted DamID with next-generation sequencing. Nature Protocols 11(9), 1586-1598.
Southall, T.D., Gold, K.S., Egger, B., Davidson, C.M., Caygill, E.E., Marshall, O.J. and Brand, A.H. (2013). Cell type-specific profiling of gene expression and chromatin binding without cell isolation: Assaying RNA Pol II occupancy in neural stem cells. Developmental Cell 26, 101-112.