Using human induced pluripotent stem cells to investigate the roles of astrocytes in spinal muscular atrophy

Spinal muscular atrophy (SMA) is a neuromuscular disease caused by the mutation of SMN1 gene and which is characterized by the selective degeneration of lower motor neurons. Through the years, it has become more evident that SMA is not solely a disease of the lower motor neurons, but other cell type...

Full description

Saved in:
Bibliographic Details
Main Author: Loh, Sharon Jia Hui
Other Authors: Albert I. Chen
Format: Theses and Dissertations
Language:English
Published: 2018
Subjects:
Online Access:http://hdl.handle.net/10356/74828
Tags: Add Tag
No Tags, Be the first to tag this record!
Institution: Nanyang Technological University
Language: English
id sg-ntu-dr.10356-74828
record_format dspace
spelling sg-ntu-dr.10356-748282023-02-28T18:42:23Z Using human induced pluripotent stem cells to investigate the roles of astrocytes in spinal muscular atrophy Loh, Sharon Jia Hui Albert I. Chen School of Biological Sciences A*STAR Genome Institute of Singapore Lawrence W Stanton DRNTU::Science::Biological sciences::Molecular biology Spinal muscular atrophy (SMA) is a neuromuscular disease caused by the mutation of SMN1 gene and which is characterized by the selective degeneration of lower motor neurons. Through the years, it has become more evident that SMA is not solely a disease of the lower motor neurons, but other cell types within and outside the brain were also found to be dysfunctional. The non-cell autonomous roles of astrocytes in influencing neuronal survival in neurodegenerative diseases is an emerging concept and has only been well-described in ALS. Till date, the involvement of astrocytes, which make up the majority of the cell population in the CNS, is still poorly understood in SMA. In this thesis, WT and SMA human iPSC-derived astrocytes and motor neurons were generated with high efficiencies and were used as a paradigm to investigate underlying dysregulated molecular pathways in SMA astrocytes and to uncover aberrant interactions between SMA motor neurons and astrocytes. Global gene expression profiling revealed that SMA astrocytes were hyper-reactive based on their upregulated expression of genes involved in ECM remodeling (MMP9 and MMP13) and inflammation (IL32 and CXCL6). Functional characterizations showed that SMA astrocytes were incapable of eliciting calcium signaling and taking up extracellular glutamate, suggesting ineffective synaptic transmissions and induction of neuronal excitotoxicity respectively. Coculture experiments indicated that SMA astrocytes augmented their reactivity upon exposure to WT and SMA motor neurons and produced elevated levels of MMP9. The increase in astrocytic reactivity and net secretory MMP9 levels in SMA astrocytes cocultures correlated with motor neuronal demise. Collectively, results obtained in this research show that SMA astrocytes are defective and play important roles in influencing motor neuron survivability in SMA. ​Doctor of Philosophy (SBS) 2018-05-24T05:09:12Z 2018-05-24T05:09:12Z 2018 Thesis Loh, S. J. H. (2018). Using human induced pluripotent stem cells to investigate the roles of astrocytes in spinal muscular atrophy. Doctoral thesis, Nanyang Technological University, Singapore. http://hdl.handle.net/10356/74828 en 265 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Science::Biological sciences::Molecular biology
spellingShingle DRNTU::Science::Biological sciences::Molecular biology
Loh, Sharon Jia Hui
Using human induced pluripotent stem cells to investigate the roles of astrocytes in spinal muscular atrophy
description Spinal muscular atrophy (SMA) is a neuromuscular disease caused by the mutation of SMN1 gene and which is characterized by the selective degeneration of lower motor neurons. Through the years, it has become more evident that SMA is not solely a disease of the lower motor neurons, but other cell types within and outside the brain were also found to be dysfunctional. The non-cell autonomous roles of astrocytes in influencing neuronal survival in neurodegenerative diseases is an emerging concept and has only been well-described in ALS. Till date, the involvement of astrocytes, which make up the majority of the cell population in the CNS, is still poorly understood in SMA. In this thesis, WT and SMA human iPSC-derived astrocytes and motor neurons were generated with high efficiencies and were used as a paradigm to investigate underlying dysregulated molecular pathways in SMA astrocytes and to uncover aberrant interactions between SMA motor neurons and astrocytes. Global gene expression profiling revealed that SMA astrocytes were hyper-reactive based on their upregulated expression of genes involved in ECM remodeling (MMP9 and MMP13) and inflammation (IL32 and CXCL6). Functional characterizations showed that SMA astrocytes were incapable of eliciting calcium signaling and taking up extracellular glutamate, suggesting ineffective synaptic transmissions and induction of neuronal excitotoxicity respectively. Coculture experiments indicated that SMA astrocytes augmented their reactivity upon exposure to WT and SMA motor neurons and produced elevated levels of MMP9. The increase in astrocytic reactivity and net secretory MMP9 levels in SMA astrocytes cocultures correlated with motor neuronal demise. Collectively, results obtained in this research show that SMA astrocytes are defective and play important roles in influencing motor neuron survivability in SMA.
author2 Albert I. Chen
author_facet Albert I. Chen
Loh, Sharon Jia Hui
format Theses and Dissertations
author Loh, Sharon Jia Hui
author_sort Loh, Sharon Jia Hui
title Using human induced pluripotent stem cells to investigate the roles of astrocytes in spinal muscular atrophy
title_short Using human induced pluripotent stem cells to investigate the roles of astrocytes in spinal muscular atrophy
title_full Using human induced pluripotent stem cells to investigate the roles of astrocytes in spinal muscular atrophy
title_fullStr Using human induced pluripotent stem cells to investigate the roles of astrocytes in spinal muscular atrophy
title_full_unstemmed Using human induced pluripotent stem cells to investigate the roles of astrocytes in spinal muscular atrophy
title_sort using human induced pluripotent stem cells to investigate the roles of astrocytes in spinal muscular atrophy
publishDate 2018
url http://hdl.handle.net/10356/74828
_version_ 1759856039507787776