E-Thesis 398 views 1157 downloads
Inhibiting IL-17 Production by Blocking Endogenous RORγt Agonists for the Treatment of Autoimmune Diseases / DAPHNE DAVIES
Swansea University Author: DAPHNE DAVIES
DOI (Published version): 10.23889/SUthesis.60183
Abstract
The expression of pro-inflammatory cytokine IL-17 has been implicated in the pathogenesis of various autoimmune diseases. This project investigates the role of the cholesterol metabolising enzyme, CYP7B1 in the generation of the endogenous ligand of the master transcription factor, RORγt, driving th...
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Swansea
2022
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| Institution: | Swansea University |
| Degree level: | Doctoral |
| Degree name: | Ph.D |
| Supervisor: | Griffiths, William J. ; Thornton, Cathy ; Mullins, Jonathan |
| URI: | https://cronfa.swan.ac.uk/Record/cronfa60183 |
| Abstract: |
The expression of pro-inflammatory cytokine IL-17 has been implicated in the pathogenesis of various autoimmune diseases. This project investigates the role of the cholesterol metabolising enzyme, CYP7B1 in the generation of the endogenous ligand of the master transcription factor, RORγt, driving the production of pro-inflammatory cytokine, IL-17 in Th17 cells. Oxysterols are oxidised derivatives of cholesterol which are intermediates in bile acid synthesis and have more recently been shown to have biological activity including roles in lipid homeostasis and immunity. This study uses an enzyme assisted derivatistion method with HPLC-ESI-MSn for free and total sterol analysis of CD4+ T cells from cell cultures isolated from healthy human donors. Inhibition of CYP7B1 activity with azole compounds is confirmed in vitro with Th17 differentiated cells isolated from healthy human donors and LC-MS analysis of oxysterols 24(S),25-diHC and 7α,24,25-triHC, upstream and downstream of CYP7B1 activity respectively. The activity of potent LXR agonist 24(S),25-EC, which is produced abundantly in CD4+ T cells, and downstream metabolites towards RORγt is investigated in vitro with CD4+ T cells from healthy human donors. The pathway in which 24(S),25-EC is deactivated in CD4+ T cells through CYP7B1 and HSD3B7 is revealed and the mechanism which determines agonists or inverse agonists activity of oxysterols towards RORγt is demonstrated through in silico molecular modelling. This study provides the foundations to progress the understanding of the role of oxysterols as RORγt ligands in Th17 cells. Further investigation may reveal a potential new target for the treatment of autoimmune diseases in which elevated Th17 cells and IL-17 production are observed. |
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| College: |
Faculty of Medicine, Health and Life Sciences |