Interleukin-37 isoform A (IL-37a) is a novel regulator of immune cell function

Hameed, Najwa Jameel (2018) Interleukin-37 isoform A (IL-37a) is a novel regulator of immune cell function. PhD thesis, University of Glasgow.

Abstract

Background: Interleukin (IL)-37 is a newly identified member of IL-1 cytokine family, and has five isoforms (IL-37a-e). While the function of IL-37b has been well studied as an important immunosuppressive cytokine that plays an antiinflammatory role in several diseases, the functions of other IL-37 isoforms are largely unknown. The five IL-37 isoforms are varying in protein sequences, induction and tissue distribution, suggesting that the isoforms may differ in function. This study was focusedon the IL-37a isoform, with IL-37b as a control. This was because our preliminary results showed that IL-37a expression is highly inducible in human macrophages by inflammatory stimuli compared to other IL37 isoforms, suggesting that IL-37a may play an important role in inflammatory response. Furthermore, IL-37a protein is different from other IL-37 isoforms, in particular the N- terminal which contains a nuclear localisation sequence (NLS) and an elastase cleave site, suggesting that IL-37a may have unique biochemical features and functions.
Hypothesis: Based on the differences at the N-terminal, IL-37a and IL-37b isoforms may differ in cellular location and function. Based on protein sequence similarities with IL-37b at the C-terminal, which contains the IL-1 domain for receptor binding and signalling. IL-37a may be also bioactive by signalling via the same receptor as IL-37b. Aim: To address the hypothesis, I set out the following aims: 1) to produce recombinant IL-37a and IL-37b proteins and compare their differences in protein levels (Chapter 3). 2) To investigate whether IL-37a is bioactive and what is the difference between IL-37a and b in the regulation of Toll-like receptor (TLR)- induced inflammatory response in immune cells (Chapter 4). 3) To explore the molecular mechanism by which IL-37a and b differently regulate inflammatory gene profiles and signalling pathways by transcriptomics.
Methods: To investigate their effect and difference in bioactivity, I produced recombinant IL-37a and b in Escherichia coli (E.coli) system and purified by affinity chromatography and gel filtration (Chapter 3). The effect of IL-37a and IL-37b on the regulation of TLR-induced inf ii compared in macrophages and in B cells in vitro (Chapter 4). The B cells from IL37a transgenic (IL-37a-tg) mice and wild type (wt) control mice were used for studying the effect of IL-37a on B cell functions (Chapter 4). The microarray and bioinformatics analysis was used to unravel the differences between IL-37a and b in term of genes regulation and signalling pathways in lipopolysaccharide (LPS)- stimulated spleenocytes from IL37a and b transgenic and wt control mice (Chapter 5).

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: IL-37a, IL-37b, immune cells, B cells, medical biochemistry.
• Subjects: Q Science > QH Natural history > QH345 Biochemistry
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Infection & Immunity > Immunology & Infection
• Supervisor's Name: Xu, Dr. Damo and Walker, Professor Daniel
• Date of Award: 2018
• Depositing User: Ms Najwa Hameed
• Unique ID: glathesis:2018-71939
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 15 May 2019 10:16
• Last Modified: 19 Jul 2019 10:49
• URI: https://theses.gla.ac.uk/id/eprint/71939