The effect of small molecule analogues of the immunomodulatory helminth product ES-62 on denritic cell responses

Student thesis: Doctoral Thesis

Abstract

ES-62, a glycoprotein secreted by the parasitic filarial nematode Acanthocheilonema viteae, targets immune system cells including dendritic cells (DCs), to subvert inflammatory responses. The post-translational addition of phosphorylcholine (PC) is responsible for many of the immunomodulatory properties of this molecule and as ES-62 is potentially immunogenic, and therefore unsuitable as a drug, a library of small molecule analogues (SMAs) of ES-62 based on its PC moiety has been synthesised. The aim of this project was to investigate the effects of these SMAs on DCs. From a library of 79 compounds, 6 SMAs (11a, 12b, 11e, 11h, 11i and 11k) were selected as they significantly down-regulated LPS-induced cytokine production in vitro. ES-62 requires TLR4 and MyD88 to mediate many of its anti-inflammatory effects. However, cytokine inhibition mediated by SMAs 11a, 12b, 11e and 11i is generally intact in TLR4 knock-out (KO) and MyD88 KO bmDCs. Cytokine inhibition was found to be mediated through inhibition of LPS-induced cytokine gene expression and to be associated with reduction in LPS-induced activation of NF-κBp655, and MAPKs p38 and ERK. The SMAs also suppress LPS-induced up-regulation of CD40 and CD86; priming a DC phenotype that inhibits the production of IFN-γ by naïve T cells in vitro. Pre-exposure of DCs to 11a or 11i prior to LPS stimulation in vitro primes the cells to suppress the expansion of Ag-specific T cells in vivo, and this is associated with significantly inhibited numbers of IL-17A+CD4+ cells. Furthermore, mice subjected to collagen-induced arthritis pre-treated with 11a/12b-DCs had significantly reduced disease compared to mice inoculated with untreated DCs, and this was accompanied by a significant inhibition of IL-17+ cells in the draining lymph nodes. Thus overall this study has found that SMAs based on the PC moiety of ES-62 can modulate DCs such that they prime reduced TH17 responses in vivo.
Date of Award1 Oct 2015
LanguageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsUniversity of Strathclyde & BBSRC (Biotech & Biological Sciences Research Council)
SupervisorWilliam Harnett (Supervisor) & Dino Rotondo (Supervisor)

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