Regulation of the NLRP3 Inflammasome by Cathepsin Z

Campden, Rhiannon I

Regulation of the NLRP3 Inflammasome by Cathepsin Z

dc.contributor.advisor	Yates, Robin M.
dc.contributor.author	Campden, Rhiannon I
dc.contributor.committeemember	Hollenberg, Morley
dc.contributor.committeemember	Shi, Yan
dc.contributor.committeemember	Khrisendath, Chadee
dc.contributor.committeemember	Akkari, Leila
dc.date	Fall Convocation
dc.date.accessioned	2022-11-15T17:43:27Z
dc.date.embargolift	2022-07-06
dc.date.issued	2020-07-06
dc.description.abstract	The focus of this dissertation is on understanding how cathepsin Z is involved in the initiation of inflammation, and specifically, how cathepsin Z contributes to the production of interleukin (IL)-1? following NLRP3 inflammasome activation. IL-1? is a pro-inflammatory cytokine involved in the recruitment of immune cells and the polarization of TH17 cells. Activation of the NLRP3 inflammasome, which is a macromolecular complex composed of a receptor (NLRP3), an adaptor protein (ASC), and the protease caspase-1, leads to cleavage and release of IL-1?. Cathepsin Z contains dual functions as a C-terminal exopeptidase and an integrin-binding protein. Initially, we explored the involvement of cathepsin Z in the development of inflammation in a mouse model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE). We found that cathepsin Z is required for the recruitment of immune cells into the central nervous system (CNS). Here, we found cathepsin Z is involved in TH17 polarization due to reduced IL-1?, but not antigen processing, T cell activation nor T cell migration. This led us to investigate the mechanism through which cathepsin Z regulates IL-1? production. We found that extracellular cathepsin Z signals through the ?5 integrin following NLRP3 inflammasome activation. Furthermore, the function of cathepsin Z in this context was dependent on the integrin-binding domain of cathepsin Z and not its proteolytic activity. This reveals another mechanism of NLRP3 regulation through an endogenous extracellular protein that signals through integrins. Finally, we employed proteomic and degradomic approaches following NLRP3 inflammasome activation in the absence of NLRP3 to gain a deeper understanding of the proteins involved in NLRP3 inflammasome activation. In the absence of NLRP3, caspase-1 and IL-1? are degraded, while caspase-4 is stabilized. Further, ROS levels are lower following NLRP3 inflammasome activation with silica in the absence of NLRP3, and the expression of several mitochondrial proteins are deregulated, suggesting the importance of the mitochondria and ROS signalling in NLRP3 inflammasome activation. Collectively, this dissertation reveals a novel extracellular regulatory pathway of the NLRP3 inflammasome and further outlines the signalling function of cathepsin Z in inflammation. This dissertation also presents a dataset of proteins for investigation in NLRP3 inflammasome activation.
dc.identifier.citation	Campden, R. I. (2020). Regulation of the NLRP3 Inflammasome by Cathepsin Z (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.
dc.identifier.uri	http://hdl.handle.net/1880/115493
dc.identifier.uri	https://dx.doi.org/10.11575/PRISM/40460
dc.language.iso	en	en
dc.language.iso	English
dc.publisher.faculty	Graduate Studies	en
dc.publisher.faculty	Cumming School of Medicine
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
dc.subject	Inflammasome
dc.subject	Cathepsins
dc.subject	Cathepsin Z
dc.subject	Integrin
dc.subject	Multiple Sclerosis
dc.subject	Experimental Autoimmune Encephalomyelitis
dc.subject	Inflammation
dc.subject	Interleukin-1
dc.subject	Th17 cells
dc.subject	caspase-1
dc.subject	Silicosis
dc.subject	Mass Spectrometry
dc.subject	Terminal amine isotopic labeling of substrates
dc.subject.classification	Biology--Molecular
dc.subject.classification	Biology--Cell
dc.title	Regulation of the NLRP3 Inflammasome by Cathepsin Z
dc.type	doctoral thesis
thesis.degree.discipline	Biological Sciences
thesis.degree.grantor	University of Calgary	en
thesis.degree.grantor	University of Calgary
thesis.degree.name	Doctor of Philosophy (PhD)