Investigating the Role of BTK in Microglia in Multiple Sclerosis and its Animal Models

Li, Cenxiao

Investigating the Role of BTK in Microglia in Multiple Sclerosis and its Animal Models

dc.contributor.advisor	Yong, Voon Wee
dc.contributor.author	Li, Cenxiao
dc.contributor.committeemember	Ousman, Shalina
dc.contributor.committeemember	Lohman, Alex
dc.contributor.committeemember	Jirik, Frank
dc.date	2023-11
dc.date.accessioned	2023-09-18T14:49:57Z
dc.date.available	2023-09-18T14:49:57Z
dc.date.issued	2023-09-07
dc.description.abstract	Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) characterized by demyelination, immune cell infiltration and neurodegeneration. A class of drugs, Bruton’s tyrosine kinase (BTK) inhibitors are currently undergoing phase III clinical trials for the treatment of MS. BTK inhibitors primarily target the activity of B cells, but BTK activation is also downstream of pro-inflammatory signalling pathways in CNS myeloid cells, microglia, and macrophages. Existing research into the role of BTK signalling in microglia and macrophages is cursory, and the connection between BTK expression and pro-inflammatory activities remains to be elucidated. In this thesis, the expression of BTK was evaluated in the CNS tissue of MS and its rodent models, and the effect of BTK inhibition in the experimental autoimmune encephalomyelitis (EAE) model and on microglia in a co-culture system was investigated. In MS brain samples, we observed the expression of BTK and (the active form) pBTK in areas with a high immunoreactivity of Iba1+ microglia/macrophages. In three animal models of MS, BTK and pBTK were observed to be upregulated in the spinal cord lesions, but only pBTK expression was downregulated at later time points. Lineage tracing of CNS macrophages revealed that both microglia and macrophages express BTK and pBTK without a preference by either cell type. Treatment of MOG¬35-55 EAE mice with the BTK inhibitor GDC-0853 initiated from EAE induction day showed significant reduction in the clinical and histological pathologies. However, drug administration from clinical onset only showed marginal reductions in overall clinical signs, and immunofluorescent analyses of the spinal cord lesions did not show detectable differences in the expression of myeloid, myelin and axonal markers. In vitro, stimulation of neuron-microglia co-culture with IFN-γ and LPS resulted in robust neuronal death and elevated secretion of TNF-α, which were not attenuated with the addition of GDC-0853. Drug treatment of microglia activated with iLPS did not show reduced expression of pBTK. These results suggest that BTK inhibition may effectively reduce disease pathophysiology if treatment is initiated early, but its capacity to directly modulate microglial activities remains to be established.
dc.identifier.citation	Li, C. (2023). Investigating the role of BTK in microglia in multiple sclerosis and its animal models (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.
dc.identifier.uri	https://hdl.handle.net/1880/117023
dc.identifier.uri	https://doi.org/10.11575/PRISM/41866
dc.language.iso	en
dc.publisher.faculty	Cumming School of Medicine
dc.publisher.institution	University of Calgary
dc.rights	University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subject	multiple sclerosis
dc.subject	Bruton’s tyrosine kinase
dc.subject	neuroinflammation
dc.subject	microglia
dc.subject	animal models
dc.subject.classification	Neuroscience
dc.subject.classification	Immunology
dc.title	Investigating the Role of BTK in Microglia in Multiple Sclerosis and its Animal Models
dc.type	master thesis
thesis.degree.discipline	Medicine – Neuroscience
thesis.degree.grantor	University of Calgary
thesis.degree.name	Master of Science (MSc)
ucalgary.thesis.accesssetbystudent	I require a thesis withhold – I need to delay the release of my thesis due to a patent application, and other reasons outlined in the link above. I have/will need to submit a thesis withhold application.