The most highly evolved structure in the human brain is the neocortex, which is responsible for the higher cognitive functions unique to humans. Despite its importance, little research has been done to understand how the human neocortex develops, especially during the period when most neurogenesis takes place, the second trimester of gestation. We have recently characterized a unique population of neural stem cells (oRG cells) in the developing human neocortex responsible for the majority of cortical neuron production. These cells reside in a germinal region known as the outer subventricular zone (OSVZ). Notably, the OSVZ is not found in the rodent, implying that using the rodent as a model system to understand human neocortical development has significant limitations.
The aim of the proposed research is to further understand the mechanisms by which OSVZ progenitor cells contribute to human neocortical development, focusing on four areas: 1) the origin of oRG cells and their neural stem cell properties;2) the cellular and molecular mechanisms that maintain oRG cell identity and self-renewal during neurogenesis;3) the amplifying divisions that oRG cell daughters undergo to increase neuronal production;and 4) how oRG cells are required for the production and correct layering of neuronal subtypes in the neocortex. With innovative approaches such as cell labeling and clonal analysis, real-time imaging of cellular behaviors, and molecular genetic techniques in organotypic slice-cultures, the proposed research aims to provide a solid new foundation for understanding human neocortical development. This framework will be essential to correctly understand human neurological diseases that have genetic or developmental origins, ranging from cortical malformations such as lissencephaly and microcephaly to more subtle defects like epilepsy, autism, and schizophrenia. Knowing the proper developmental sequences by which cortical neurons are generated will also be important for cellular regeneration or transplantation therapies for neurological diseases.
The human cerebral cortex is the most highly evolved structure in the human brain and is the site of higher cognitive functions unique to the human species. This study investigates the cellular and molecular mechanisms of human cortex development, focusing on a unique population of neural stem cells not described in rodents. A better understanding of how the human cortex has grown in size and complexity could shed light on a wide assortment of neurodevelopmental disorders, ranging from cortical malformations including microcephaly and lissencephaly to more subtle diseases such as autism and schizophrenia.
|Bershteyn, Marina; Nowakowski, Tomasz J; Pollen, Alex A et al. (2017) Human iPSC-Derived Cerebral Organoids Model Cellular Features of Lissencephaly and Reveal Prolonged Mitosis of Outer Radial Glia. Cell Stem Cell 20:435-449.e4|
|Subramanian, Lakshmi; Bershteyn, Marina; Paredes, Mercedes F et al. (2017) Dynamic behaviour of human neuroepithelial cells in the developing forebrain. Nat Commun 8:14167|
|Retallack, Hanna; Di Lullo, Elizabeth; Arias, Carolina et al. (2016) Zika virus cell tropism in the developing human brain and inhibition by azithromycin. Proc Natl Acad Sci U S A 113:14408-14413|
|Diaz, Aaron; Liu, Siyuan J; Sandoval, Carmen et al. (2016) SCell: integrated analysis of single-cell RNA-seq data. Bioinformatics 32:2219-20|
|Nowakowski, Tomasz J; Pollen, Alex A; Di Lullo, Elizabeth et al. (2016) Expression Analysis Highlights AXL as a Candidate Zika Virus Entry Receptor in Neural Stem Cells. Cell Stem Cell 18:591-6|
|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|
|Nowakowski, Tomasz J; Pollen, Alex A; Sandoval-Espinosa, Carmen et al. (2016) Transformation of the Radial Glia Scaffold Demarcates Two Stages of Human Cerebral Cortex Development. Neuron 91:1219-1227|
|Pollen, Alex A; Nowakowski, Tomasz J; Chen, Jiadong et al. (2015) Molecular identity of human outer radial glia during cortical development. Cell 163:55-67|
|Lui, Jan H; Nowakowski, Tomasz J; Pollen, Alex A et al. (2014) Radial glia require PDGFD-PDGFR? signalling in human but not mouse neocortex. Nature 515:264-8|
|Pollen, Alex A; Nowakowski, Tomasz J; Shuga, Joe et al. (2014) Low-coverage single-cell mRNA sequencing reveals cellular heterogeneity and activated signaling pathways in developing cerebral cortex. Nat Biotechnol 32:1053-8|
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