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The Role of IL-1R8 in Modulating Macrophage Inflammation: Implications for Atherosclerosis.
|Title:||The Role of IL-1R8 in Modulating Macrophage Inflammation: Implications for Atherosclerosis.|
|Authors:||Liu, Chloe Anne O. Y.|
|Contributors:||Molecular Biosciences & Bioeng (department)|
|Date Issued:||Aug 2017|
|Publisher:||University of Hawaiʻi at Mānoa|
|Abstract:||Atherosclerosis is a chronic inflammatory disease of the cardiovascular system|
characterized by macrophage-driven arterial plaque accumulation. Interleukin (IL)-37 is an antiinflammatory
cytokine within the IL-1 family which suppresses inflammatory immune response
by complexing with the receptors IL-1R8 and IL-18Rα. Because IL-37 and its receptor are
robustly expressed in the macrophage, I sought to determine if IL-1R8 plays a key role in
macrophage inflammation that may in turn influence the development of atherosclerosis.
Initially the proposed anti-inflammatory effects of IL-37 was investigated by co-treating
mice bone marrow-derived macrophages (BMDM) with recombinant IL-37 protein and various
inflammatory stimuli. Although inflammation was not quelled by IL-37, interestingly, IL-1R8
was consistently downregulated by LPS and IFNg treatment. To test whether IL-1R8 inhibits
inflammation, I overexpressed IL-1R8 in the mouse macrophage cell line, RAW 264.7 cells, and
BMDM by transfection with IL-1R8 or GFP expression plasmids. Transfected cells were treated
with pro-inflammatory (LPS, IFNg, TNFa) or anti-inflammatory (IL-4) mediators, as well as IL-
37. Transfection of RAW 264.7 cells with IL-1R8 resulted in 35-to-60-fold increases of IL-1R8
transcript expression compared to controls as measured by RT-qPCR, whereas IL-1R8 protein
level was increased 6 to9 folds compared to GFP-transfected control cells, as measured by
Western blot. Interestingly, transfection with IL-1R8 resulted in robust overexpression of IL-1R8
with a molecular weight of 70-95 kDa, indicating significant glycosylation, which was confirmed
by glycosidase treatment. In contrast to my initial hypothesis, overexpression of IL-1R8 in RAW
cells and BMDM had a pro-inflammatory effect overall. However, when treated with
recombinant IL-37 protein as the ligand for IL-1R8, the IL-1R8-transfected RAW cells showed
reduced inflammatory gene expression compared to GFP controls treated with the same stimulus.
Additionally, siRNA knockdown of IL-1R8 resulted in significantly higher inflammatory gene
expression, such as IL-6, IL-1b, iNOS, MCP1/CCL2, and TNFa in both RAW 264.7 cells and
BMDM. The experiments described show that IL-1R8, along with its ligand IL-37, plays a role
in regulating macrophage inflammation, although future studies are needed to further elucidate
its exact molecular mechanism.
|Description:||M.S. Thesis. University of Hawaiʻi at Mānoa 2017.|
|Rights:||All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.|
|Appears in Collections:||
M.S. - Molecular Biosciences and Bioengineering|
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