The human brain is made up of neurons and glia. Glia comprise about 90% of brain cells and are involved in devastating disorders such as multiple sclerosis, seizures and Alzheimer's disease. We know little about development of the most prevalent glial cells called astrocytes. This proposal will identify fundamental mechanisms by which neural stem cells give rise to astrocytes. It is also intended to generate useful markers to investigate roles for astrocytes during development and in human disease. The goal of the proposed research is to identify a set of genetic markers for development of astrocytes and to map their cellular origins in the central nervous system. The underlying hypothesis to be tested is that astrocytes develop from heterogeneous locations in the developing CMS. We have three specific aims:
Specific Aim 1 is to identify and characterize activity of transcription factors that uniquely mark and may regulate astrocyte development. In preliminary work, we have interrogated the mammalian transcriptome to identify transcription factors that co-localize with astrocytes in the developing spinal cord. Expression analysis and gain- and Ioss-of-function screens will be conducted to prioritize generation of antibodies to transcription factors that mark and may regulate astrocyte lineage heterogeneity in the CNS.
Specific Aim 2 is to develop cell type- and stage-specific markers for fibrous and protoplasmic astrocytes. We have developed fluorescent activated cell sorting (FACS) protocols for acute harvest of gray matter astrocytes and analysis by expression profiling. By sorting cells from Gensat transgenic mice that express green fluorescent protein (GFP) in (1) pan-astroglial and (2) white matter astrocyte compartments, we will identify markers specific for fibrous astrocytes, protoplasmic astrocytes and astrocyte precursors in various CNS regions.
Specific Aim 3 is to determine whether astrocyte diversity correlates with developmental site of origin in the embryonic spinal cord and brain. We will use a cohort of cre/lox transgenic mice to fate map heterogeneous progenitor domains for astrocytes and their ultimate cellular origins in the embryonic CNS. Based on information obtained in Aims1/2, we will generate a floxed conditional reporter transgenic mouse Iine that will express the FACS-selectable marker GFP exclusively in astroglia. This will enable acute purification of astrocyte subsets for further discrimination of astrocyte heterogeneity.
These studies will elucidate the mechanisms by which neural stem cells give rise to astrocytes and provide useful genetic tools for understanding the diverse roles of astrocytes in human development, with practical implications for diagnosis and treatment of human disorders such as epilepsy, brain cancer and neurodegeneration.
|Bayraktar, Omer Ali; Fuentealba, Luis C; Alvarez-Buylla, Arturo et al. (2014) Astrocyte development and heterogeneity. Cold Spring Harb Perspect Biol 7:a020362|
|Molofsky, Anna V; Kelley, Kevin W; Tsai, Hui-Hsin et al. (2014) Astrocyte-encoded positional cues maintain sensorimotor circuit integrity. Nature 509:189-94|
|Molofsky, Anna V; Glasgow, Stacey M; Chaboub, Lesley S et al. (2013) Expression profiling of Aldh1l1-precursors in the developing spinal cord reveals glial lineage-specific genes and direct Sox9-Nfe2l1 interactions. Glia 61:1518-32|
|Stephan, Alexander H; Madison, Daniel V; Mateos, José María et al. (2013) A dramatic increase of C1q protein in the CNS during normal aging. J Neurosci 33:13460-74|
|Tien, An-Chi; Tsai, Hui-Hsin; Molofsky, Anna V et al. (2012) Regulated temporal-spatial astrocyte precursor cell proliferation involves BRAF signalling in mammalian spinal cord. Development 139:2477-87|
|Zamanian, Jennifer L; Xu, Lijun; Foo, Lynette C et al. (2012) Genomic analysis of reactive astrogliosis. J Neurosci 32:6391-410|
|Molofsky, Anna V; Krencik, Robert; Krenick, Robert et al. (2012) Astrocytes and disease: a neurodevelopmental perspective. Genes Dev 26:891-907|
|Fancy, Stephen P J; Glasgow, Stacey M; Finley, Meggie et al. (2012) Evidence that nuclear factor IA inhibits repair after white matter injury. Ann Neurol 72:224-33|
|Fu, Hui; Kesari, Santosh; Cai, Jun (2012) Tcf7l2 is tightly controlled during myelin formation. Cell Mol Neurobiol 32:345-52|
|Heine, Vivi M; Griveau, Amelie; Chapin, Cheryl et al. (2011) A small-molecule smoothened agonist prevents glucocorticoid-induced neonatal cerebellar injury. Sci Transl Med 3:105ra104|
Showing the most recent 10 out of 15 publications