Functional role of 1q21.1 chromosomal loci on the development and physiology of neuro-immune cells

Singh, Tanya 2021. Functional role of 1q21.1 chromosomal loci on the development and physiology of neuro-immune cells. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Emerging evidence suggests that glial cells that have a role in modulating inflammation, play an active role in the pathogenesis of Neurodevelopmental and Psychiatric Disorders (NPDs), including autism spectrum disorders (ASD) and schizophrenia (SCZ). Genome-wide association studies have shown that chromosomal mutations such as Copy Number Variation (CNV) at 1q21.1 loci (deletion and duplication) are associated with significant risk for NPDs. However, the impact of this mutation on glial development and physiology and how it contributes to increased risk for NPDs remains unknown. Using patient-derived iPSCs carrying CNVs the role of 1q21.1 chromosomal locus on the functionality of neuroimmune cells-astrocytic and microglial and its contribution to disease pathology has been explored in this thesis. The result presented in this thesis demonstrated that 1q21.1 CNV is associated with altered astrocyte morphology and its effect on functional abilities like phagocytosis, glutamate uptake, ATP production, and calcium activity. Further, RNA-seq data from astrocytes carrying 1q21.1 CNV had highly significant changes in genes linked to ASD and SCZ. To study the impact of 1q21.1 CNV carrying astrocytes on neuronal health, a co-culture system was developed where astrocytes carrying 1q21.1 CNV were cultured with healthy neurons. The co-culture of healthy neurons with 1q21.1 CNV carrying astrocytes resulted in differential expression of synapse associated genes suggesting an impact on synapse formation in healthy neurons. Further, the co-culture of astrocytes carrying 1q21.1 CNV with healthy neurons resulted in increased production of reactive oxygen species, suggesting compromised neuroprotective function of astrocytes. The network activity of these co-cultures also demonstrated a deficit compared to healthy neuronal network activity as quantified by network firing rate and synchronization. To establish the role of critical genes in the 1q21.1 CNV, two knockout lines (KO-GJA5 and KO-GJA8) were generated using CRISPR technology. The functional assays performed on these lines mimic similar results as in astrocytes carrying 1q21.1 deletion. To further investigate the 1q21.1 CNV on neuroinflammatory status, the microglia like cells were derived from iPSCs. The pathway analysis of the microglia carrying 1q21.1 CNV demonstrated differential expression of essential immune and inflammation regulatory genes. Also, time and dose-dependent cytokine production were compared with human microglia. Further, the iPSC derived microglia were also used to understand the immunomodulation following traumatic brain injury. The result presented in this thesis for the first time demonstrates the contribution of 1q21.1 loci to NPDs by glial dysfunction and immunomodulatory pathways.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Biosciences
Subjects:	Q Science > Q Science (General)
Date of First Compliant Deposit:	3 May 2022
Date of Acceptance:	3 May 2022
Last Modified:	03 May 2024 01:30
URI:	https://orca.cardiff.ac.uk/id/eprint/149493

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