Macrophages are multifaceted innate immune cells, able to adapt their phenotype to respond to a myriad of conditions, engaging in tissue-specific functions and mediating either inflammatory or anti-inflammatory responses depending on the encountered stimuli. They conduct key roles in the orchestration of immune responses; from pathogen recognition through sterilising inflammation to resolution and repair. The Udalova laboratory has previously demonstrated that IRF5 promotes a pro- inflammatory macrophage phenotype, leading to the secretion of TNF, IL-12, and IL-23, enhancing Th1/Th17-mediated immune responses, and described the cooperation between IRF5 and the transcription factor RelA, which mediate the production of pro-inflammatory genes. The aim of this thesis is to further characterise the activity of IRF5 in macrophage inflammatory responses. I demonstrate that IRF5 not only regulates the transcription of cytokines and chemokines in response to bacterial stimuli, but also anti-microbial peptides, whilst simultaneously down-regulating homeostatic and resolving macrophage functions. My data also suggests that IRF5 plays a role in enforcing monocyte to macrophage differentiation by up-regulating the transcription of key macrophages markers and repressing dendritic cell identity genes. To further characterise the mechanisms of the inflammatory response mounted by macrophages I used an unbiased approach; combining twenty-three transcription factor ChIP-seq data sets with chromatin accessibility information from ATAC-seq, uncovering RUNX1 as a novel partner of IRF5 that binds co-operatively to clusters of enhancers, which control the transcription of pro-inflammatory genes in a signal-dependent manner. This is the first study demonstrating a critical role for RUNX1 in activity of inflammatory macrophages.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:748860 |
| Date | January 2017 |
| Creators | Khoyratty, Tariq |
| Contributors | Udalova, Irina ; Proudfoot, Nicholas J. |
| Publisher | University of Oxford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://ora.ox.ac.uk/objects/uuid:b820f612-ceb7-4e2c-af26-52999e368c41 |
Page generated in 0.0023 seconds