Analysis of the Trichuris suis excretory/secretory proteins as a function of life cycle stage and their immunomodulatory properties

Abstract

Parasitic worms have a remarkable ability to modulate host immune responses through several mechanisms including excreted/secreted proteins (ESP), yet the exact nature of these proteins and their targets often remains elusive. Here, we performed mass spectrometry analyses of ESP (TsESP) from larval and adult stages of the pig whipworm Trichuris suis (Ts) and identified ~350 proteins. Transcriptomic analyses revealed large subsets of differentially expressed genes in the various life cycle stages of the parasite. Exposure of bone marrow-derived macrophages and dendritic cells to TsESP markedly diminished secretion of the pro-inflammatory cytokines TNFα and IL-12p70. Conversely, TsESP exposure strongly induced release of the anti-inflammatory cytokine IL-10, and also induced high levels of nitric oxide (NO) and upregulated arginase activity in macrophages. Interestingly, TsESP failed to directly induce CD4+ CD25+ FoxP3+ regulatory T cells (Treg cells), while OVA-pulsed TsESP-treated dendritic cells suppressed antigen-specific OT-II CD4+ T cell proliferation. Fractionation of TsESP identified a subset of proteins that promoted anti-inflammatory functions, an activity that was recapitulated using recombinant T. suis triosephosphate isomerase (TPI) and nucleoside diphosphate kinase (NDK). Our study helps illuminate the intricate balance that is characteristic of parasite-host interactions at the immunological interface, and further establishes the principle that specific parasite-derived proteins can modulate immune cell functions.

Molecular and metabolomic changes in the proximal colon of pigs infected with Trichuris suis

“…Hatching of infective T. suis eggs in the pig intestine and the parasitic invasion of the mucosal layer and epithelial cells in the proximal colon to initiate intracellular larval feeding and development perturbs the cytoskeleton matrix and cell junctions 67 . These early events alter the local microbiome as parasite mucolytic components released during larval invasion provide substrates to expand bacteria such as the Mucispirillum 16 , and parasite products that facilitate tissue penetration and worm metabolism activate and react to host immune protective responses 68 . The interplay of host, parasite, and microbiome has consequences for parasite survival and the intensity and persistence of host inflammation 16 – 18 The earliest events recorded in this current study showed that at 21 DAI there was an induction of gene expression to activate type 2 related immune responses including M2a macrophage that have been shown to regulate intestinal smooth muscle function via SERPINB2 36 , and that has been linked to a STAT6-dependent effects on smooth muscle hyper-contractility associated with protection against T. muris in mice (Madden et al, unpublished).…”

Development of caecaloids to study host–pathogen interactions: new insights into immunoregulatory functions of Trichuris muris extracellular vesicles in the caecum

“…In order to persist in their host, whipworms modulate intestinal inflammation, ensuring their host’s and their own survival ( Klementowicz et al, 2012 , Grencis, 2015 ). One such mechanism of immunomodulation is the release of ES products that can interact with immune cells, the regulatory impact of which has been described ( Kuijk et al, 2012 , Klaver et al, 2013 , Laan et al, 2017 , Leroux et al, 2018 , Shears et al, 2018b , Bancroft et al, 2019 ). ES products likely act also on caecal IECs, given that whipworms live inside the epithelium; however, little is known about these interactions ( Hiemstra et al, 2014 ).…”

“…Whipworms can remain in their host for years, causing chronic infections. To optimise their residence in their hosts, whipworms manipulate host inflammation, partly through the immunoregulatory effects of ES products released by the parasites ( Kuijk et al, 2012 , Klaver et al, 2013 , Hansen et al, 2015 , Laan et al, 2017 , Tritten et al, 2017 , Eichenberger et al, 2018b , Leroux et al, 2018 , Shears et al, 2018a , Shears et al, 2018b , Bancroft et al, 2019 ). Progress has been made in understanding the composition and anti-inflammatory actions of whipworm ES products.…”

Proteomic Analysis Of Trichuris Trichiura Egg Extract Reveals Potential Immunomodulators And Diagnostic Targets

“…Parasitic worms have a remarkable ability to modulate the host immune response through several mechanisms; speci c parasitederived proteins can modulate immune functions playing an important role in the parasite-host interaction. Excretion/secretion proteins from larvae and adults of the porcine whipworm, T. suis, closely related to the human T. trichiura, were investigated by Leroux et al [21], who identi ed a subset of proteins that promote speci c anti-in ammatory functions and immunomodulatory properties.…”

“…Only a few reports indicate that they may be modulators of the immune system, and recognize them as potential sources of diagnostic antigens [17,18]. Interestingly, the administration of embryonated eggs from the animal species Trichuris suis or Trichuris muris to humans has been described as potential therapeutic agents for immune-related pathologies such as chronic intestinal in ammatory diseases, emphasizing their capacity to downregulate aberrant intestinal in ammation [6,[19][20][21][22]. Their immunomodulatory capacity continues to be investigated with some studies trying to identify the molecules responsible for those effects [14,[22][23][24][25].…”