Post-graduate theses
Current Record: 29 of 800
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| Identifier |
000457106 |
| Title |
The role of PHF8 in metabolism during macrophage activation |
| Alternative Title |
Ο ρόλος της PHF8 στη ρύθμιση μεταβολικών γονιδίων κατά την ενεργοποίηση των μακροφάγων |
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Author
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Μαράβα, Ισμήνη Α.
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Thesis advisor
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Τσατσάνης, Χρήστος
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| Abstract |
Macrophages as a population display great heterogeneity and serve various functions in
immune response including elimination of pathogens, resolution of inflammation and tissue
homeostasis. In response to different stimuli they exhibit great plasticity reflected at the
transcriptional, epigenetic and metabolic level. Metabolism has a central role during
macrophage activation. Different polarizing signals cause distinct metabolic changes, which
govern macrophage activation and support the great macrophage plasticity. PHF8 is a
Jumonji C domain containing histone lysine demethylase. Preliminary data have shown
differences in inflammatory response in Raw264.7 cells overexpressing (O/E) PHF8 and
Raw264.7 cells knock out (K.O.) for PHF8 with cells overexpressing PHF8 having lower levels
of proinflammatory markers production and K.O. cells having enhanced proinflammatory
phenotype after LPS stimulation. We performed RNA sequencing in these cells to gain
further insight into the mechanism of PHF8 regulation of immune response. The results
revealed differences in metabolic genes such as genes involved in lipid and protein
biosynthesis, whose regulation of expression by PHF8 may underlie its inhibitory role in
classic macrophage activation. In support to this notion mTORC1, a central complex which
incorporates various signals and regulates metabolic pathways was positively regulated by
PHF8 at the naïve state, but had impaired activation after LPS treatment in cells
overexpressing PHF8. mTORC1 activates Hif1a, which in turn control glycolytic gene
expression, a hallmark of M1 macrophages. Consistent with mTORC1 activation, major
glycolytic genes such as hk3 and pfkp have increased expression at the naïve state but no
further induction in PHF8 overexpressing cells, which could explain the reduced
responsiveness of PHF8 O/E cells. Additionally in the RNA sequencing results we observed
increased expression of E.R. stress induced genes, which we also validated by western blot.
The negative role of PHF8 in classic macrophage activation was also observed in mouse
BMDMs combined with enhanced TNF production at the endotoxin tolerant state in PHF8
knock down BMDMs. mTORC1 activation was also increased at the endotoxin tolerant state
in PHF8 knock down BMDMs. Last but not least we showed that PHF8 expression is induced
post α-KG treatment, a metabolite known to induce tolerance, indicating that PHF8 is a
possible mediator of this phenotype. In conclusion, we showed in the present study that the
histone demethylase PHF8 is a negative regulator of macrophage activation and an
important regulator of macrophage metabolism revealing its potential role in shaping
macrophage phenotype in the context of endotoxin tolerance.
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| Language |
English |
| Subject |
Demethylase |
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Epigenetics |
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Απομεθυλάσες |
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Επιγενετική |
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Μεταβολισμός |
| Issue date |
2023-07-28 |
| Collection
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School/Department--School of Sciences and Engineering--Department of Biology--Post-graduate theses
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Type of Work--Post-graduate theses
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| Permanent Link |
https://elocus.lib.uoc.gr//dlib/6/e/c/metadata-dlib-1689069337-960359-31659.tkl
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| Views |
512 |
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