Neural stem cells (NSCs) hold promise for the treatment of a wide range of neurological disorders common to Veterans such as traumatic brain injury (TBI) and Parkinson's disease. In addition to providing cells for transplantation-based therapies, NSCs are also an important source of human neurons and glia for drug discovery and development. To realize the full potential of NSCs for human therapy, it is important to understand the molecular mechanisms that regulate the production of specific neural cell types. Our long-term goal is to understand the cellular and molecular mechanisms by which NSCs produce specific types of neurons and glia. The postnatal and adult mammalian brain harbors NSCs in the ventricular-subventricular zone (V- SVZ). Importantly, V-SVZ NSCs retain distinct regional identities that underlie the production of different neuronal subtypes. For instance, NSCs in the ventral V-SVZ produce neuron subtypes different from those born from NSCs in the dorsal V-SVZ. Furthermore, such NSC regional identity is largely cell-intrinsic, and we have shown that NSCs ?remember? their regional identity through serial cell divisions. The expression of Nkx2.1 defines a population of NSCs in the ventral V-SVZ. While sonic hedgehog (SHH) is required to induce Nkx2.1 expression in ventral NSCs of the early embryonic brain, our Preliminary Studies indicate that SHH- signaling is not required for the maintenance of Nkx2.1 expression in ventral V-SVZ NSCs, suggesting that these cells epigenetically ?remember? their regional identity. Mixed lineage leukemia-1 (Mll1) encodes a chromatin regulator that is part of an evolutionarily conserved transcriptional memory system, and MLL1 is required for normal V-SVZ neurogenesis. We found MLL1 protein enriched at Nkx2.1 regulatory elements, and disruption of MLL1 activity with either conditional Mll1 deletion or an MLL1-specific chemical inhibitor resulted in the loss of Nkx2.1 expression in ventral V-SVZ NSCs. After reversal of MLL1 inhibition, Nkx2.1 expression remained low, but neuronal production was restored. Based on these findings, our central hypothesis is that MLL1 is required to maintain NSC regional identity via specific chromatin state changes. In this renewal application, we propose to investigate the role of MLL1 in NSC regional identity and determine the molecular mechanisms by which MLL1 maintains region-specific gene expression. Given that NSC regional identity is a critical aspect of their neurogenic potential, results obtained will have important implications for our ability to produce specific types of neurons for human translational research and transplantation therapies. Furthermore, these studies advance new basic, neurodevelopmental concepts regarding NSC regional identity, which may be important to understanding how mutations in human MLL1 cause Weidemann-Steiner Syndrome, a developmental disorder that includes intellectual disability and autism. Finally, discovering MLL1-dependent mechanisms at genomic regulatory elements will likely be of interest to the broader fields of neurodevelopment, epigenetics and stem cell biology. Our Preliminary Studies, expertise in V-SVZ and chromatin biology, and our productive collaborations with Dr. Aaron Diaz (for bioinformatics innovation and support), support the feasibility of this project.

Public Health Relevance

Neural stem cells (NSCs) hold promise for the treatment of neurological disorders, and understanding the molecular mechanisms by which NSCs differentiate into specific types of neurons and glia is key to unlocking their therapeutic potential. Our overall goal is to determine the molecular mechanisms that regulate NSC biology. For NSCs to make neurons, daughter cells need to express certain sets of genes while repressing others. Such lineage-specific gene expression is in part regulated by chromatin structure ? the ?packaged? state of DNA. We plan to use cell biology and molecular approaches to investigate how the MLL1 chromatin regulator coordinates the production of specific types of neurons from NSCs. Results from these proposed studies may advance our ability to develop new therapeutics for neurological disorders common to the Veteran population such as traumatic brain injury and Parkinson's disease.

National Institute of Health (NIH)
Veterans Affairs (VA)
Non-HHS Research Projects (I01)
Project #
Application #
Study Section
Cellular and Molecular Medicine (CAMM)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Veterans Affairs Medical Center San Francisco
San Francisco
United States
Zip Code
Delgado, Ryan N; Lim, Daniel A (2017) Maintenance of Positional Identity of Neural Progenitors in the Embryonic and Postnatal Telencephalon. Front Mol Neurosci 10:373
Liu, S John; Horlbeck, Max A; Cho, Seung Woo et al. (2017) CRISPRi-based genome-scale identification of functional long noncoding RNA loci in human cells. Science 355:
Diaz, Aaron; Liu, Siyuan J; Sandoval, Carmen et al. (2016) SCell: integrated analysis of single-cell RNA-seq data. Bioinformatics 32:2219-20
Müller, Sören; Liu, Siyuan John; Di Lullo, Elizabeth et al. (2016) Single-cell sequencing maps gene expression to mutational phylogenies in PDGF- and EGF-driven gliomas. Mol Syst Biol 12:889
Ramos, Alexander D; Attenello, Frank J; Lim, Daniel A (2016) Uncovering the roles of long noncoding RNAs in neural development and glioma progression. Neurosci Lett 625:70-9
Liu, Siyuan John; Nowakowski, Tomasz J; Pollen, Alex A et al. (2016) Single-cell analysis of long non-coding RNAs in the developing human neocortex. Genome Biol 17:67
Rolston, John D; Ramos, Alexander D; Heath, Susan et al. (2015) Thalamotomy-Like Effects From Partial Removal of a Ventral Intermediate Nucleus Deep Brain Stimulator Lead in a Patient With Essential Tremor: Case Report. Neurosurgery 77:E831-6; discussion E836-7
Delgado, Ryan N; Lim, Daniel A (2015) Embryonic Nkx2.1-expressing neural precursor cells contribute to the regional heterogeneity of adult V-SVZ neural stem cells. Dev Biol 407:265-74
Ramos, Alexander D; Andersen, Rebecca E; Liu, Siyuan John et al. (2015) The long noncoding RNA Pnky regulates neuronal differentiation of embryonic and postnatal neural stem cells. Cell Stem Cell 16:439-447
Park, Dae Hwi; Hong, Sung Jun; Salinas, Ryan D et al. (2014) Activation of neuronal gene expression by the JMJD3 demethylase is required for postnatal and adult brain neurogenesis. Cell Rep 8:1290-9

Showing the most recent 10 out of 15 publications