Limiting Autoimmune Neuroinflammation using Novel T Cell Suppressants & Investigating Overlapping Lysosomal Reductase Function in Macrophages and Osteoclasts

Ewanchuk, Benjamin Walter

Limiting Autoimmune Neuroinflammation using Novel T Cell Suppressants & Investigating Overlapping Lysosomal Reductase Function in Macrophages and Osteoclasts

dc.contributor.advisor	Yates, Robin M.
dc.contributor.advisor	Ramachandran, Rithwik
dc.contributor.author	Ewanchuk, Benjamin Walter
dc.contributor.committeemember	Ousman, Shalina S.
dc.contributor.committeemember	Riabowol, Karl T.
dc.date	2019-11
dc.date.accessioned	2019-07-15T21:05:32Z
dc.date.available	2019-07-15T21:05:32Z
dc.date.issued	2019-07-19
dc.description.abstract	Aberrant activation of adaptive immune cells can culminate in autoimmune diseases such as multiple sclerosis (MS). Recently, potent anti-inflammatory properties for the cooling compound, icilin, and its receptor target, Transient Receptor Potential Melastatin-8 (TRPM8), were characterized in the context of inflammatory colitis—the first half of this dissertation describes an attempt to repurpose the anti-inflammatory qualities of icilin and TRPM8 for the treatment of lymphocyte-mediated neuroinflammation. We found icilin treatment strongly attenuated experimental autoimmune encephalomyelitis (EAE), a murine model of MS, via an unexpected TRPM8-independent mechanism. Icilin inhibited the proliferation, polarization and downstream effector function of CD4+ T cells, suggesting a promising drug for limiting neuroinflammation. Citing the advantageous pharmacodynamics of icilin, we additionally screened a library of icilin-related analogues for anti-proliferative character. We identified several lead compounds with improved anti-proliferative properties compared to icilin in vitro and preliminary efficacy in vivo limiting EAE severity. Collectively, this work characterizes a new class of T cell suppressants while emphasizing clear off-target effects for the cooling drug icilin beyond TRP channel activation. Antigen presenting cells such as macrophages process phagocytosed cargo within the highly degradative phagolysosome, facilitating antigenic stimulation of T cells and adaptive immunity. The redox microenvironment of the phagolysosomal lumen regulates several phagolysosomal biochemistries, including proteolysis and disulfide reduction. The lysosomal enzyme γ-interferon-inducible lysosomal thiol reductase (GILT) directly catalyzes disulfide reduction and enhances proteolysis by thiol-dependent cysteine cathepsins within the phagolysosome—while clearly implicated in antigen processing, secondary roles for GILT remain largely undefined. The second half of this dissertation establishes a role for GILT in osteoclasts, bone resorbing cells derived from macrophages. GILT expression was highly upregulated in osteoclasts in response to osteoclastogenic and inflammatory cytokines, and GILT-deficient mice were discovered to be osteopetrotic. In vitro, GILT-deficient osteoclasts demonstrated a reduced capacity to resorb bone. GILT not only directly reduced disulfides within bone matrix structural proteins, but also enhanced the activity of cathepsin K, the prototypical osteoclast collagenase. Thus, this work reveals a novel, non-immunological role for GILT in osteoclast function and bone turnover.	en_US
dc.identifier.citation	Ewanchuk, B. W. (2019). Limiting Autoimmune Neuroinflammation using Novel T Cell Suppressants & Investigating Overlapping Lysosomal Reductase Function in Macrophages and Osteoclasts (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.	en_US
dc.identifier.doi	http://dx.doi.org/10.11575/PRISM/36749
dc.identifier.uri	http://hdl.handle.net/1880/110642
dc.language.iso	eng	en_US
dc.publisher.faculty	Cumming School of Medicine	en_US
dc.publisher.institution	University of Calgary	en
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.	en_US
dc.subject	Icilin	en_US
dc.subject	TRPM8	en_US
dc.subject	Multiple Sclerosis	en_US
dc.subject	EAE	en_US
dc.subject	T Cell	en_US
dc.subject	GILT	en_US
dc.subject	Redox	en_US
dc.subject	Osteoclast	en_US
dc.subject	Macrophage	en_US
dc.subject	Lysosome	en_US
dc.subject	Cathepsin	en_US
dc.subject.classification	Immunology	en_US
dc.subject.classification	Biochemistry	en_US
dc.title	Limiting Autoimmune Neuroinflammation using Novel T Cell Suppressants & Investigating Overlapping Lysosomal Reductase Function in Macrophages and Osteoclasts	en_US
dc.type	doctoral thesis	en_US
thesis.degree.discipline	Medicine – Biochemistry and Molecular Biology	en_US
thesis.degree.grantor	University of Calgary	en_US
thesis.degree.name	Doctor of Philosophy (PhD)	en_US
ucalgary.item.requestcopy	true	en_US