Lisa C. Laan

Trichuris suis-induced modulation of human dendritic cell function is glycan-mediated.

Human monocyte-derived dendritic cells (DCs) show remarkable phenotypic changes upon direct contact with soluble products (SPs) of Trichuris suis, a pig whipworm that is experimentally used in therapies to ameliorate inflammation in patients with Crohns disease and multiple sclerosis. These changes may contribute to the observed induction of a T helper 2 (Th2) response and the suppression of Toll-like receptor (TLR)-induced Th1 and Th17 responses by human DCs primed with T. suis SPs. Here it is demonstrated that glycans of T. suis SPs contribute significantly to the suppression of the lipopolysaccharide (LPS)-induced expression in DCs of a broad variety of cytokines and chemokines, including important pro-inflammatory mediators such as TNF-α, IL-6, IL-12, lymphotoxin α (LTA), C-C Motif Ligand (CCL)2, C-X-C Motif Ligands (CXCL)9 and CXCL10. In addition, the data show that human DCs strongly bind T. suis SP-glycans via the C-type lectin receptors (CLRs) mannose receptor (MR) and DC-specific ICAM-3-grabbing non-integrin (DC-SIGN). The interaction of DCs with T. suis glycans likely involves mannose-type glycans, rather than fucosylated glycans, which differs from DC binding to soluble egg antigens of the human worm parasite, Schistosoma mansoni. In addition, macrophage galactose-type lectin (MGL) recognises T. suis SPs, which may contribute to the interaction with immature DCs or other MGL-expressing immune cells such as macrophages. The interaction of T. suis glycans with CLRs of human DCs may be essential for the ability of T. suis to suppress a pro-inflammatory phenotype of human DCs. The finding that the T. suis-induced modulation of human DC function is glycan-mediated is novel and indicates that helminth glycans contribute to the dampening of inflammation in a wide range of human inflammatory diseases.

The helminth Trichuris suis suppresses TLR4-induced inflammatory responses in human macrophages.

Recent clinical trials in patients with inflammatory diseases like multiple sclerosis (MS) or inflammatory bowel disease (IBD) have shown the beneficial effects of probiotic helminth administration, although the underlying mechanism of action remains largely unknown. Potential cellular targets may include innate immune cells that propagate inflammation in these diseases, like pro-inflammatory macrophages. We here investigated the effects of the helminth Trichuris suis soluble products (SPs) on the phenotype and function of human inflammatory (granulocyte-macrophage colony-stimulating factor (GM-CSF)-differentiated) macrophages. Interestingly, we here show that T. suis SPs potently skew inflammatory macrophages into a more anti-inflammatory state in a Toll-like receptor 4 (TLR4)-dependent manner, and less effects are seen when stimulating macrophages with TLR2 or -3 ligands. Gene microarray analysis of GM-CSF-differentiated macrophages further revealed that many TLR4-induced inflammatory mediators, including interleukin (IL)-12B, CCL1 and CXCL9, are downregulated by T. suis SPs. In particular, we observed a strong reduction in the expression and function of P2RX7, a purinergic receptor involved in macrophage inflammation, leading to reduced IL-1β secretion. In conclusion, we show that T. suis SPs suppress a broad range of inflammatory pathways in GM-CSF-differentiated macrophages in a TLR4-dependent manner, thereby providing enhanced mechanistic insight into the therapeutic potential of this helminth for patients with inflammatory diseases.

Treatment with Trichuris suis soluble products during monocyte-to-macrophage differentiation reduces inflammatory responses through epigenetic remodeling

Helminths have strong immunoregulatory properties that may be exploited in treatment of chronic immune disorders, such as multiple sclerosis and inflammatory bowel disease. Essential players in the pathogenesis of these diseases are proinflammatory macrophages. We present evidence that helminths modulate the function and phenotype of these innate immune cells. We found that soluble products derived from the Trichuris suis (TsSP) significantly affect the differentiation of monocytes into macrophages and their subsequent polarization. TsSPs reduce the expression and production of inflammatory cytokines, including IL‐6 and TNF, in human proinflammatory M1 macrophages. TsSPs induce a concomitant anti‐inflammatory M2 signature, with increased IL‐10 production. Furthermore, they suppress CHIT activity and enhance secretion of matrix metalloproteinase 9. Short‐term triggering of monocytes with TsSPs early during monocyte‐to‐macrophage differentiation imprinted these phenotypic alterations, suggesting long‐lasting epigenetic changes. The TsSP‐induced effects in M1 macrophages were completely reversed by inhibiting histone deacetylases, which corresponded with decreased histone acetylation at the TNF and IL6 promoters. These results demonstrate that TsSPs have a potent and sustained immunomodulatory effect on human macrophage differentiation and polarization through epigenetic remodeling and provide new insights into the mechanisms by which helminths modulate human immune responses.—Hoeksema, M. A., Laan, L. C., Postma, J. J., Cummings, R. D., de Winther, M. P. J., Dijkstra, C. D., van Die, I., Kooij, G. Treatment with Trichuris suis soluble products during monocyte‐to‐macrophage differentiation reduces inflammatory responses through epigenetic remodeling. FASEB J. 30, 2826‐2836 (2016). www.fasebj.org

Trichuris suis soluble products induce Rab7b expression and limit TLR4 responses in human dendritic cells

Inflammatory immune disorders such as inflammatory bowel disease and multiple sclerosis are major health problems. Currently, the intestinal whipworm Trichuris suis is being explored in clinical trials to reduce inflammation in these diseases; however, the mechanisms by which the parasite affects the host immune system are not known. Here we determined the effects of T. suis soluble products (SPs) on Toll-like receptor-4 (TLR4)-stimulated human dendritic cells (DCs) using Illumina bead chip gene arrays. Pathway analysis of lipopolysaccharide-stimulated DCs with or without T. suis treatment showed that co-stimulation with T. suis SPs resulted in a downregulation of both the myeloid differentiation primary response gene 88-dependent and the TIR-domain-containing adaptor-inducing interferon-β-dependent signalling pathways triggered by TLR4. These data were verified using quantitative real-time PCR of several key genes within these pathways and/or defining their protein levels. In addition, T. suis SPs induce Rab7b, a negative regulator of TLR4 signalling that interferes with its trafficking, which coincided with a reduced surface expression of TLR4. These data indicate that the mechanism by which T. suis SPs reduce inflammatory responses is through suppression of both TLR4 signalling and surface expression on DCs.

The whipworm (Trichuris suis) secretes prostaglandin E2 to suppress proinflammatory properties in human dendritic cells

Clinical trials have shown that administration of the nematode Trichuris suis can be beneficial in treating various immune disorders. To provide insight into the mechanisms by which this worm suppresses inflammatory responses, an active component was purified from T. suis soluble products (TsSPs) that suppress TNF and IL‐12 secretion from LPS‐activated human dendritic cells (DCs). Analysis by liquid chromatography tandem mass spectrometry identified this compound as prostaglandin (PG)E2. The purified compound showed similar properties compared with TsSPs and commercial PGE2 in modulating LPS‐induced expression of many cytokines and chemokines and in modulating Rab7B and P2RX7 expression in human DCs. Furthermore, the TsSP‐induced reduction of TNF secretion from DCs is reversed by receptor antagonists for EP2 and EP4, indicating PGE2 action. T. suis secretes extremely high amounts of PGE2 (45–90 ng/mg protein) within their excretory/secretory products but few related lipid mediators as established by metabololipidomic analysis. Culture of T. suis with several cyclooxygenase (COX) inhibitors that inhibit mammalian prostaglandin synthesis affected the worms motility but did not inhibit PGE2 secretion, suggesting that the worms can synthesize PGE2 via a COX‐independent pathway. We conclude that T. suis secretes PGE2 to suppress proinflammatory responses in human DCs, thereby modulating the hosts immune response.—Laan, L. C., Williams, A. R., Stavenhagen, K., Giera, M., Kooij, G., Vlasakov, I., Kalay, H., Kringel, H., Nejsum, P., Thamsborg, S. M., Wuhrer, M., Dijkstra, C. D., Cummings, R. D., van Die, I. The whipworm (Trichuris suis) secretes prostaglandin E2 to suppress proinflammatory properties in human dendritic cells. FASEB J. 31, 719–731 (2017). http://www.fasebj.org

Trichuris suis induces human non-classical patrolling monocytes via the mannose receptor and PKC: implications for multiple sclerosis

IntroductionThe inverse correlation between prevalence of auto-immune disorders like the chronic neuro-inflammatory disease multiple sclerosis (MS) and the occurrence of helminth (worm) infections, suggests that the helminth-trained immune system is protective against auto-immunity. As monocytes are regarded as crucial players in the pathogenesis of auto-immune diseases, we explored the hypothesis that these innate effector cells are prime targets for helminths to exert their immunomodulatory effects.ResultsHere we show that soluble products of the porcine nematode Trichuris suis (TsSP) are potent in changing the phenotype and function of human monocytes by skewing classical monocytes into anti-inflammatory patrolling cells, which exhibit reduced trans-endothelial migration capacity in an in vitro model of the blood–brain barrier. Mechanistically, we identified the mannose receptor as the TsSP-interacting monocyte receptor and we revealed that specific downstream signalling occurs via protein kinase C (PKC), and in particular PKCδ.ConclusionThis study provides comprehensive mechanistic insight into helminth-induced immunomodulation, which can be therapeutically exploited to combat various auto-immune disorders.

Co-operative suppression of inflammatory responses in human dendritic cells by plant proanthocyanidins and products from the parasitic nematode Trichuris suis

Interactions between dendritic cells (DCs) and environmental, dietary and pathogen antigens play a key role in immune homeostasis and regulation of inflammation. Dietary polyphenols such as proanthocyanidins (PAC) may reduce inflammation, and we therefore hypothesized that PAC may suppress lipopolysaccharide (LPS) ‐induced responses in human DCs and subsequent T helper type 1 (Th1) ‐type responses in naive T cells. Moreover, we proposed that, because DCs are likely to be exposed to multiple stimuli, the activity of PAC may synergise with other bioactive molecules that have anti‐inflammatory activity, e.g. soluble products from the helminth parasite Trichuris suis (TsSP). We show that PAC are endocytosed by monocyte‐derived DCs and selectively induce CD86 expression. Subsequently, PAC suppress the LPS‐induced secretion of interleukin‐6 (IL‐6) and IL‐12p70, while enhancing secretion of IL‐10. Incubation of DCs with PAC did not affect lymphocyte proliferation; however, subsequent interferon‐γ production was markedly suppressed, while IL‐4 production was unaffected. The activity of PAC was confined to oligomers (degree of polymerization ≥ 4). Co‐pulsing DCs with TsSP and PAC synergistically reduced secretion of tumour necrosis factor‐α, IL‐6 and IL‐12p70 while increasing IL‐10 secretion. Moreover, both TsSP and PAC alone induced Th2‐associated OX40L expression in DCs, and together synergized to up‐regulate OX40L. These data suggest that PAC induce an anti‐inflammatory phenotype in human DCs that selectively down‐regulates Th1 response in naive T cells, and that they also act cooperatively with TsSP. Our results indicate a novel interaction between dietary compounds and parasite products to influence immune function, and may suggest that combinations of PAC and TsSP can have therapeutic potential for inflammatory disorders.

Hypoxia inducible factor 1α down regulates cell surface expression of α1,2-fucosylated glycans in human pancreatic adenocarcinoma cells

The α1,2‐fucosyltransferase activity in pancreatic tumors is much lower compared to normal pancreatic tissue. Here we show that hypoxia inducible factor (HIF) 1α is constitutively expressed in the pancreatic cancer cell lines Pa‐Tu‐8988S and Pa‐Tu‐8988T and suppresses the expression of the α1,2‐fucosyltransferase genes FUT1 and FUT2. Down regulation of HIF‐1α expression resulted in elevated FUT1 and FUT2 transcript levels and an increased expression of α1,2‐fucosylated glycan structures on the surface of these cells. In conclusion, our data are the first to identify HIF‐1α as a suppressor of FUT1/2 expression, thereby regulating α1,2‐fucosylation of cell‐surface glycans.

Pleurotus citrinopileatus polysaccharide stimulates anti-inflammatory properties during monocyte-to-macrophage differentiation

Polysaccharides from edible mushrooms possess important immunomodulating effects on immune cells including monocytes and macrophages. Macrophages activated by LPS/IFNγ are polarized toward inflammatory macrophages, whereas the anti-inflammatory properties of alternative activated macrophages play an important regulatory role in the innate immune system. We here show that the Pleurotus citrinopileatus mushroom polysaccharide (PCPS) can modulate the monocyte-to-macrophage differentiation early at the monocyte stage. Using both human THP-1 monocytic cells as well as human peripheral monocytes, we showed that PCPS inhibits the secreted levels of the pro-inflammatory cytokines TNF and IL-6, after stimulation of macrophages derived from PCPS-treated monocytes, with IFNγ + LPS. In addition, the glucan induced a tendency to increase the secreted levels of the anti-inflammatory cytokine IL-10, enhanced the expression levels of CCL2 and CCL8 mRNAs, and inhibited expression of CCR2 mRNA in the IFNγ/LPS activated macrophages. Interestingly, these data suggest that PCPS can induce a long-lasting anti-inflammatory effect in monocytes. Treatment of monocytes with laminarin and antibodies against Dectin-1 and TLR2 during PCPS treatment affected the glucan-modulated macrophage differentiation. In summary, the results of this study indicate that the glucan directs the differentiation of monocytes toward a macrophage cell population with reduced pro-inflammatory capacity via Dectin-1 and TLR2.