{"id":{"repo_id":"cambridge","oai_identifier":"oai:www.repository.cam.ac.uk:1810/311008"},"canonical_url":"https://search.dev.ndltd.org/etd/cambridge/oai:www.repository.cam.ac.uk:1810/311008","repository":{"repo_id":"cambridge","name":"Cambridge University","base_url":"https://api.repository.cam.ac.uk/server/oai/request"},"display":{"title":"Macrophage Response to Interleukin-1 Stimulation and the Nature of Cell Surface Interleukin-1 Alpha","abstract":"Interleukin-1α (IL-1α) is a potent cytokine involved in a range of diseases and can be found expressed on the cell surface (csIL-1α) and in the soluble form, signalling through the type I IL-1 receptor (IL-1R1). IL-1 signalling leads to increased secretion of cytokines, recruitment of immune cells thus perpetuating a highly inflammatory environment. It has been the understanding for years that IL-1R1 is present on many cell types including macrophages and monocytes. We report that there can be false positive staining of target proteins if a permeability stain is not introduced. Thus, we show that when gated on intact cells, there is no IL-1R1 expressed on macrophages or dendritic cells, and when IL-1R1 is overexpressed, IL-1 signalling can occur. We also suggest that the mere presence of IL-1R1 is not sufficient to lead to IL-1 signalling, but that there is a minimum threshold of IL-1R1 expression for that to occur, illustrating a novel checkpoint mechanism to prevent aberrant IL-1 signalling. In the second part of this project, we investigated the nature of csIL-1α, reported to be crucial for the senescence-associated secretory phenotype (SASP). We show that pro-IL-1α is synthesised de novo and trafficked to the membrane following TLR4 stimulation. We report two novel ways by which csIL-1α can be bound, through the type II IL-1 receptor (IL-1R2) and glycosylphosphatidylinositol (GPI) anchors. IL-1R2 is responsible for majority of the csIL-1α binding to the cell membrane with a small portion of csIL-1α being tethered to a GPI- associated protein. We report that csIL-1α is significantly downregulated by IFNγ treatment but intracellular and secreted IL-1α levels are not affected by this. In conclusion, this thesis has contributed to a better understanding of IL-1 signalling through IL-1R1 and its regulation. It has also enhanced the understanding of csIL-1α binding and mechanisms that affect its expression.","abstract_html":"Interleukin-1α (IL-1α) is a potent cytokine involved in a range of diseases and can be found expressed on the cell surface (csIL-1α) and in the soluble form, signalling through the type I IL-1 receptor (IL-1R1). IL-1 signalling leads to increased secretion of cytokines, recruitment of immune cells thus perpetuating a highly inflammatory environment. It has been the understanding for years that IL-1R1 is present on many cell types including macrophages and monocytes. We report that there can be false positive staining of target proteins if a permeability stain is not introduced. Thus, we show that when gated on intact cells, there is no IL-1R1 expressed on macrophages or dendritic cells, and when IL-1R1 is overexpressed, IL-1 signalling can occur. We also suggest that the mere presence of IL-1R1 is not sufficient to lead to IL-1 signalling, but that there is a minimum threshold of IL-1R1 expression for that to occur, illustrating a novel checkpoint mechanism to prevent aberrant IL-1 signalling. In the second part of this project, we investigated the nature of csIL-1α, reported to be crucial for the senescence-associated secretory phenotype (SASP). We show that pro-IL-1α is synthesised de novo and trafficked to the membrane following TLR4 stimulation. We report two novel ways by which csIL-1α can be bound, through the type II IL-1 receptor (IL-1R2) and glycosylphosphatidylinositol (GPI) anchors. IL-1R2 is responsible for majority of the csIL-1α binding to the cell membrane with a small portion of csIL-1α being tethered to a GPI- associated protein. We report that csIL-1α is significantly downregulated by IFNγ treatment but intracellular and secreted IL-1α levels are not affected by this. In conclusion, this thesis has contributed to a better understanding of IL-1 signalling through IL-1R1 and its regulation. It has also enhanced the understanding of csIL-1α binding and mechanisms that affect its expression.","abstract_has_math":false,"creators":["Chan, Nuo En"],"institution":"University of Cambridge","degree_name":"Doctor of Philosophy (PhD)","degree_level":"Doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Clarke, Murray"],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020-02-01","date_published":"2020-02-01","updated_at":"2026-07-22T22:24:03Z","subjects":["Interleukin-1","cell surface Interleukin-1 alpha"],"languages":["eng"],"rights":[],"rights_urls":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/2c5dda4e-5e90-41f8-bf1c-e1183174051e/download","https://www.rioxx.net/licenses/all-rights-reserved/"],"identifier_entries":[{"key":"dc:creator.authoridentifier","label":"Author Identifier","values":["0000000280432190","0000000282158885"],"render_values":[{"text":"0000-0002-8043-2190","href":"https://orcid.org/0000-0002-8043-2190","code":true},{"text":"0000-0002-8215-8885","href":"https://orcid.org/0000-0002-8215-8885","code":true}]}]},"links":{"outbound_url":"https://doi.org/10.17863/CAM.58099","outbound_label":"DOI","outbound_source":"dc:identifier.doi"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Clarke, Murray"]},{"key":"dc:creator","label":"Author","values":["Chan, Nuo En"]},{"key":"dc:creator.authoridentifier","label":"Author Identifier","values":["0000000280432190","0000000282158885"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2020-02-01"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Cambridge"]},{"key":"dc:relation.isreferencedby.uri","label":"Dc Relation Isreferencedby URI","values":["https://www.repository.cam.ac.uk/handle/1810/311008"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["Doctor of Philosophy (PhD)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Interleukin-1","cell surface Interleukin-1 alpha"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/2c5dda4e-5e90-41f8-bf1c-e1183174051e/download","https://www.rioxx.net/licenses/all-rights-reserved/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.doi","label":"DOI","values":["10.17863/CAM.58099"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/e4025663-65a2-411b-aad3-e0648b87dcac/download"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Interleukin-1α (IL-1α) is a potent cytokine involved in a range of diseases and can be found expressed on the cell surface (csIL-1α) and in the soluble form, signalling through the type I IL-1 receptor (IL-1R1). IL-1 signalling leads to increased secretion of cytokines, recruitment of immune cells thus perpetuating a highly inflammatory environment. It has been the understanding for years that IL-1R1 is present on many cell types including macrophages and monocytes. We report that there can be false positive staining of target proteins if a permeability stain is not introduced. Thus, we show that when gated on intact cells, there is no IL-1R1 expressed on macrophages or dendritic cells, and when IL-1R1 is overexpressed, IL-1 signalling can occur. We also suggest that the mere presence of IL-1R1 is not sufficient to lead to IL-1 signalling, but that there is a minimum threshold of IL-1R1 expression for that to occur, illustrating a novel checkpoint mechanism to prevent aberrant IL-1 signalling. In the second part of this project, we investigated the nature of csIL-1α, reported to be crucial for the senescence-associated secretory phenotype (SASP). We show that pro-IL-1α is synthesised de novo and trafficked to the membrane following TLR4 stimulation. We report two novel ways by which csIL-1α can be bound, through the type II IL-1 receptor (IL-1R2) and glycosylphosphatidylinositol (GPI) anchors. IL-1R2 is responsible for majority of the csIL-1α binding to the cell membrane with a small portion of csIL-1α being tethered to a GPI- associated protein. We report that csIL-1α is significantly downregulated by IFNγ treatment but intracellular and secreted IL-1α levels are not affected by this. In conclusion, this thesis has contributed to a better understanding of IL-1 signalling through IL-1R1 and its regulation. 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It has been the understanding for years that IL-1R1 is present on many cell types including macrophages and monocytes. We report that there can be false positive staining of target proteins if a permeability stain is not introduced. Thus, we show that when gated on intact cells, there is no IL-1R1 expressed on macrophages or dendritic cells, and when IL-1R1 is overexpressed, IL-1 signalling can occur. We also suggest that the mere presence of IL-1R1 is not sufficient to lead to IL-1 signalling, but that there is a minimum threshold of IL-1R1 expression for that to occur, illustrating a novel checkpoint mechanism to prevent aberrant IL-1 signalling. In the second part of this project, we investigated the nature of csIL-1α, reported to be crucial for the senescence-associated secretory phenotype (SASP). We show that pro-IL-1α is synthesised de novo and trafficked to the membrane following TLR4 stimulation. We report two novel ways by which csIL-1α can be bound, through the type II IL-1 receptor (IL-1R2) and glycosylphosphatidylinositol (GPI) anchors. IL-1R2 is responsible for majority of the csIL-1α binding to the cell membrane with a small portion of csIL-1α being tethered to a GPI- associated protein. We report that csIL-1α is significantly downregulated by IFNγ treatment but intracellular and secreted IL-1α levels are not affected by this. In conclusion, this thesis has contributed to a better understanding of IL-1 signalling through IL-1R1 and its regulation. 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