eprintid: 10199370 rev_number: 12 eprint_status: archive userid: 699 dir: disk0/10/19/93/70 datestamp: 2024-11-15 12:34:28 lastmod: 2024-11-15 12:34:28 status_changed: 2024-11-15 12:34:28 type: thesis metadata_visibility: show sword_depositor: 699 creators_name: Zhang, Xiang title: CD36 regulates macrophage and endothelial cell activation and multinucleate giant cell formation in Anti Neutrophil Cytoplasm Antibody vasculitis ispublished: unpub divisions: UCL divisions: B02 divisions: C10 divisions: D17 note: Copyright © The Author 2024. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. abstract: ANCA associated vasculitis (AAV) is characterised by monocyte/macrophage activation and small blood vessel damage leading to complications such as kidney failure. In some patients, macrophage activation leads to giant cell and granuloma formation, resulting in tissue damage. CD36 is a transmembrane glycoprotein that is expressed on the surface of various cells, such as macrophages and vascular endothelial cells. CD36 is a crucial factor in the modulation of inflammatory processes and immune reactions. However, the specific role of CD36 in AAV has remained incompletely elucidated; Therefore, I investigated CD36 and its downstream signalling pathways in macrophages, endothelial cells and multinucleated giant cell formation in AAV patients and age matched controls. CD36 expression was found to be increased in AAV kidney biopsies on macrophages. Additionally, CD36 expression on classical and intermediate monocytes was significantly increased in both PR3- and MPO-AAV patients compared to healthy controls, regardless of disease activity status. Increased levels of soluble CD36 (sCD36) were observed in the plasma of AAV patients, both in PR3-and MPO-ANCA subtypes, also in both remission and active disease. Cell surface CD36 and sCD36 were increased on cells and in supernatants from THP1-derived macrophages and Human Dermal Microvascular Endothelial Cells (HDMEC) stimulated by Palmitic acid (PA) or TNF-α respectively and was attenuated by CD36 knockdown. Stimulation of THP1-derived macrophages with PA also generated M1 polarised macrophages with significant macrophage migration inhibitory factor (MIF) production and increased expression of c-Myc. In addition, there was an increase in multinucleate giant cell (MNGC) formation. These findings were all attenuated by CD36 knockdown and MIF antagonism. Similarly, PA stimulation of vascular endothelial cells increased CD36 and vascular cell adhesion molecule-1 (VCAM-1) expression and promoted MIF production, both attenuated by CD36 knockdown. Co-culture of endothelial cells and macrophages with PA resulted in increased migration of macrophages towards the activated endothelial cells and increased macrophage activation, while these findings were inhibited by CD36 knockdown. Only a small proportion of our patients produced anti-CD36 antibodies and these did not interfere with PA-stimulated CD36-mediated signalling. While levels of free fatty acids were not elevated in AAV patients’ plasma, oxidised-LDL, another CD36 ligand was. These data suggest that CD36 and one of its ligands are abnormally expressed in AAV patients. Signalling through CD36 may potentially explain many of the features found in AAV and contribute to persistent immune activation in some patients. Targeting CD36 or its downstream effectors MIF and c-Myc may represent a novel therapeutic strategy to be tested in AAV. date: 2024-10-28 date_type: published oa_status: green full_text_type: other thesis_class: doctoral_open thesis_award: Ph.D language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 2332113 lyricists_name: Zhang, Xiang lyricists_id: XZHAK05 actors_name: Zhang, Xiang actors_id: XZHAK05 actors_role: owner full_text_status: public pages: 242 institution: UCL (University College London) department: Division of Medicine thesis_type: Doctoral citation: Zhang, Xiang; (2024) CD36 regulates macrophage and endothelial cell activation and multinucleate giant cell formation in Anti Neutrophil Cytoplasm Antibody vasculitis. Doctoral thesis (Ph.D), UCL (University College London). Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10199370/2/Zhang_10199370_thesis.pdf