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Title: Epigenetic regulation during human macrophage differentiation and polarization
Author: Yildirim-Buharalioglu , Gokce
ISNI:       0000 0004 6059 0233
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2016
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Macrophages play critical roles in initiation and resolution of inflammatory/immune responses. Divergent macrophage polarization in response to interferon-gamma (IFN-y) or interleukin-4 (IL-4) underlies a substantial part of this dichotomous behaviour owing to secretion of pro- or anti-inflammatory cytokines and matrix metalloproteinases (MMPs) or tissue inhibitors of matrix metalloproteinases (TIMPs). Transcriptional activation of these genes is well described but the role of epigenetic regulation is less clear. We used a focussed RT-qPCR array to identify epigenetic regulators whose expression is primed by IFN-y or IL-4 in human monocyte derived macrophages (HMDMs). Amongst the significant changes in 11 out of 84 genes we observed, AURKB, ESC02, SUV39Hl and WHSCI occurred secondary to inhibition of proliferation, whereas expression of the other 7 genes was direct. Because a histone3 tri-methyl lysine (H3K27met3) specific de-methylase 6B (KDM6B) was significantly increased after IFN-y or IL-4, we next performed a microarray study using GSK-J4, a pharmacological inhibitor of KDM6 family demethylases, to investigate the consequences on macrophage polarization. Microarray results were validated by RT-qPCR and shRNA silencing of KDM6A or KDM6B. 21 % of IFN-y stimulated genes (including CCL7 and VAMP5) and 11 % of IL-4 stimulated genes (including PALLD and CD206) were KDM6-dependent. GSK-J4 also inhibited expression of 485 genes (including TIMP-3, CCND1 and TRIBl) in non-activated macrophages. KDM6B silencing decreased basal TIMP-3 and inhibition by GSK-J4 increased H3K27met3 at the TIMP-3 promoter. GSK-J4 had no effect on inhibition of TIMP-3 by IFN-y, which was instead accompanied by a fall in H3K27 acetylation (H3K27Ac) that was reversed by a histone de-acetylase inhibitor MS-275. The data imply that KDM6 histone demethylases have a wide role in inflammation, including regulating cytokine production and matrix turnover. Pharmacological use of KDM6 and HDAC inhibitors may therefore represent valuable anti-inflammatory agents.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available