Publications by authors named "Irma van Die"

81 Publications

Tumor cells express pauci- and oligomannosidic N-glycans in glycoproteins recognized by the mannose receptor (CD206).

Cell Mol Life Sci 2021 Jul 5;78(14):5569-5585. Epub 2021 Jun 5.

Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, CLS 11087 - 3 Blackfan Circle, Boston, MA, 02115, USA.

The macrophage mannose receptor (CD206, MR) is an endocytic lectin receptor which plays an important role in homeostasis and innate immunity, however, the endogenous glycan and glycoprotein ligands recognized by its C-type lectin domains (CTLD) have not been well studied. Here we used the murine MR CTLD4-7 coupled to the Fc-portion of human IgG (MR-Fc) to investigate the MR glycan and glycoprotein recognition. We probed 16 different cancer and control tissues using the MR-Fc, and observed cell- and tissue-specific binding with varying intensity. All cancer tissues and several control tissues exhibited MR-Fc ligands, intracellular and/or surface-located. We further confirmed the presence of ligands on the surface of cancer cells by flow cytometry. To characterize the fine specificity of the MR for glycans, we screened a panel of glycan microarrays. Remarkably, the results indicate that the CTLD4-7 of the MR is highly selective for specific types of pauci- and oligomannose N-glycans among hundreds of glycans tested. As lung cancer tissue and the lung cancer cell line A549 showed intense MR-Fc binding, we further investigated the MR glycoprotein ligands in those cells by immunoprecipitation and glycoproteomic analysis. All enriched glycoproteins, of which 42 were identified, contained pauci- or oligomannose N-glycans, confirming the microarray results. Our study demonstrates that the MR CTLD4-7 is highly selective for pauci- and oligomannosidic N-glycans, structures that are often elevated in tumor cells, and suggest a potential role for the MR in tumor biology.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00018-021-03863-1DOI Listing
July 2021

SARS-CoV-2 Spike Protein Interacts with Multiple Innate Immune Receptors.

bioRxiv 2020 Jul 30. Epub 2020 Jul 30.

Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.

The spike (S) glycoprotein in the envelope of SARS-CoV-2 is densely glycosylated but the functions of its glycosylation are unknown. Here we demonstrate that S is recognized in a glycan-dependent manner by multiple innate immune receptors including the mannose receptor MR/CD206, DC-SIGN/CD209, L-SIGN/CD209L, and MGL/CLEC10A/CD301. Single-cell RNA sequencing analyses indicate that such receptors are highly expressed in innate immune cells in tissues susceptible to SARS-CoV-2 infection. Binding of the above receptors to S is characterized by affinities in the picomolar range and consistent with S glycosylation analysis demonstrating a variety of N- and O-glycans as receptor ligands. These results indicate multiple routes for SARS-CoV-2 to interact with human cells and suggest alternative strategies for therapeutic intervention.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1101/2020.07.29.227462DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7402034PMC
July 2020

Differential - and Glycosphingolipid Glycosylation in Human Pancreatic Adenocarcinoma Cells With Opposite Morphology and Metastatic Behavior.

Front Oncol 2020 2;10:732. Epub 2020 Jun 2.

Department of Molecular Cell Biology and Immunology, Cancer Center Amsterdam, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.

Changes in the glycosylation profile of cancer cells have been strongly associated with cancer progression. To increase our insights into the role of glycosylation in human pancreatic ductal adenocarcinoma (PDAC), we performed a study on -glycans and glycosphingolipid (GSL) glycans of the PDAC cell lines Pa-Tu-8988T (PaTu-T) and Pa-Tu-8988S (PaTu-S). These cell lines are derived from the same patient, but show an almost opposite phenotype, morphology and capacity to metastasize, and may thus provide an attractive model to study the role of glycosylation in progression of PDAC. Gene-array analysis revealed that 24% of the glycosylation-related genes showed a ≥ 1.5-fold difference in expression level between the two cell lines. Subsequent validation of the data by porous graphitized carbon nano-liquid chromatography coupled to a tandem ion trap mass spectrometry and flow cytometry established major differences in -glycans and GSL-glycans between the cell lines, including lower levels of T and sialylated Tn (sTn) antigens, neoexpression of globosides (Gb3 and Gb4), and higher levels of gangliosides in the mesenchymal-like PaTu-T cells compared to the epithelial-like PaTu-S. In addition, PaTu-S cells demonstrated a significantly higher binding of the immune-lectins macrophage galactose-type lectin and galectin-4 compared to PaTu-T. In summary, our data provide a comprehensive and differential glycan profile of two PDAC cell lines with disparate phenotypes and metastatic behavior. This will allow approaches to modulate and monitor the glycosylation of these PDAC cell lines, which opens up avenues to study the biology and metastatic behavior of PDAC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fonc.2020.00732DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7280451PMC
June 2020

Inverse Associations of Infection and Metabolic Syndromes in Humans: A Cross-Sectional Study in Northeast Ethiopia.

Microbiol Insights 2019 22;12:1178636119849934. Epub 2019 May 22.

Department of Medical Laboratory Sciences, College of Health Science, Addis Ababa University, Addis Ababa, Ethiopia.

Background: Recent animal and retrospective human studies have demonstrated that infection may have potential to protect against development of metabolic syndromes. Thus, the aim of this study was to assess metabolic panel among egg positives and egg negatives in stool examinations. This study was a cross-sectional study, conducted involving 120 participants from endemic town (Kemise) and 61 from non-endemic town (Kombolcha), Northeast Ethiopia. Stool samples were collected and examined for and other helminths using Kato-Katz method. Furthermore, blood samples were collected and used for determination of blood sugar, lipid profile tests, insulin, and C-reactive protein. Data were analyzed using SPSS software version 20. Chi-square test, independent mean t-test, and logistic regression models were employed on data. values less than .05 were considered as statistically significant.

Results: infected participants (n = 41; all from Kemise) had significantly lower levels of fasting blood sugar, low prevalence of dyslipidemia (at least one or more abnormal lipid profile tests; total cholesterol, low-density lipoprotein cholesterol [LDL-C], high-density lipoprotein cholesterol [HDL-C], and triglycerides) as compared with controls (n = 79 in Kemise and 61 in Kombolcha). Moreover, logistic regression model indicated that with the adjusted odds ratios, there was significant inverse association between infection and impaired fasting glucose (adjusted odds ratio -0.181, 95% confidence interval: 0.042-0.774).

Conclusions: Low fasting blood sugar and reduced prevalence of dyslipidemia in egg positive participants might suggest inverse association of infection and development of metabolic syndromes. Furthermore, large-scale studies are recommended to assess the role of egg and/or worm antigens in modulating the host metabolic profile and reducing the risk of metabolic syndromes, including diabetes mellitus and cardiovascular diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/1178636119849934DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6537292PMC
May 2019

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

Int J Biol Macromol 2019 Feb 27;122:705-712. Epub 2018 Oct 27.

Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijbiomac.2018.10.157DOI Listing
February 2019

Lectin-mediated binding and sialoglycans of porcine surfactant protein D synergistically neutralize influenza A virus.

J Biol Chem 2018 07 16;293(27):10646-10662. Epub 2018 May 16.

From the Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands.

Innate immunity is critical in the early containment of influenza A virus (IAV) infection, and surfactant protein D (SP-D) plays a crucial role in the pulmonary defense against IAV. In pigs, which are important intermediate hosts during the generation of pandemic IAVs, SP-D uses its unique carbohydrate recognition domain (CRD) to interact with IAV. An -linked CRD glycosylation provides interactions with the sialic acid-binding site of IAV, and a tripeptide loop at the lectin-binding site facilitates enhanced interactions with IAV glycans. Here, to investigate both mechanisms of IAV neutralization in greater detail, we produced an -glycosylated neck-CRD fragment of porcine SP-D (RpNCRD) in HEK293 cells. X-ray crystallography disclosed that the -glycan did not alter the CRD backbone structure, including the lectin site conformation, but revealed a potential second nonlectin-binding site for glycans. IAV hemagglutination inhibition, IAV aggregation, and neutralization of IAV infection studies showed that RpNCRD, unlike the human analogue RhNCRD, exhibits potent neutralizing activity against pandemic A/Aichi/68 (H3N2), enabled by both porcine-specific structural features of its CRD. MS analysis revealed an -glycan site-occupancy of >98% at Asn-303 of RpNCRD with complex-type, heterogeneously branched and predominantly α(2,3)-sialylated oligosaccharides. Glycan-binding array data characterized both RpNCRD and RhNCRD as mannose-type lectins. RpNCRD also bound Lewis structures, whereas RhNCRD bound polylactosamine-containing glycans. The presence of the -glycan in the CRD increases the glycan-binding specificity of RpNCRD. These insights increase our understanding of porcine-specific innate defense against pandemic IAV and may inform the design of recombinant SP-D-based antiviral drugs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.RA117.001430DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6036198PMC
July 2018

The Mannose Receptor in Regulation of Helminth-Mediated Host Immunity.

Front Immunol 2017 29;8:1677. Epub 2017 Nov 29.

Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States.

Infection with parasitic helminths affects humanity and animal welfare. Parasitic helminths have the capacity to modulate host immune responses to promote their survival in infected hosts, often for a long time leading to chronic infections. In contrast to many infectious microbes, however, the helminths are able to induce immune responses that show positive bystander effects such as the protection to several immune disorders, including multiple sclerosis, inflammatory bowel disease, and allergies. They generally promote the generation of a tolerogenic immune microenvironment including the induction of type 2 (Th2) responses and a sub-population of alternatively activated macrophages. It is proposed that this anti-inflammatory response enables helminths to survive in their hosts and protects the host from excessive pathology arising from infection with these large pathogens. In any case, there is an urgent need to enhance understanding of how helminths beneficially modulate inflammatory reactions, to identify the molecules involved and to promote approaches to exploit this knowledge for future therapeutic interventions. Evidence is increasing that C-type lectins play an important role in driving helminth-mediated immune responses. C-type lectins belong to a large family of calcium-dependent receptors with broad glycan specificity. They are abundantly present on immune cells, such as dendritic cells and macrophages, which are essential in shaping host immune responses. Here, we will focus on the role of the C-type lectin macrophage mannose receptor (MR) in helminth-host interactions, which is a critically understudied area in the field of helminth immunobiology. We give an overview of the structural aspects of the MR including its glycan specificity, and the functional implications of the MR in helminth-host interactions focusing on a few selected helminth species.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fimmu.2017.01677DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5712593PMC
November 2017

Profiling of different pancreatic cancer cells used as models for metastatic behaviour shows large variation in their N-glycosylation.

Sci Rep 2017 11 30;7(1):16623. Epub 2017 Nov 30.

Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands.

To characterise pancreatic cancer cells from different sources which are used as model systems to study the metastatic behaviour in pancreatic ductal adenocarcinoma (PDAC), we compared the N-glycan imprint of four PDAC cells which were previously shown to differ in their galectin-4 expression and metastatic potential in vivo. Next to the sister cell lines Pa-Tu-8988S and Pa-Tu-8988T, which were isolated from the same liver metastasis of a PDAC, this included two primary PDAC cell cultures, PDAC1 and PDAC2. Additionally, we extended the N-glycan profiling to a normal, immortalized pancreatic duct cell line. Our results revealed major differences in the N-glycosylation of the different PDAC cells as well as compared to the control cell line, suggesting changes of the N-glycosylation in PDAC. The N-glycan profiles of the PDAC cells, however, differed vastly as well and demonstrate the diversity of PDAC model systems, which ultimately affects the interpretation of functional studies. The results from this study form the basis for further biological evaluation of the role of protein glycosylation in PDAC and highlight that conclusions from one cell line cannot be generalised, but should be regarded in the context of the corresponding phenotype.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-017-16811-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5709460PMC
November 2017

Ascaris Suum Infection Downregulates Inflammatory Pathways in the Pig Intestine In Vivo and in Human Dendritic Cells In Vitro.

J Infect Dis 2018 01;217(2):310-319

Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.

Ascaris suum is a helminth parasite of pigs closely related to its human counterpart, A. lumbricoides, which infects almost 1 billion people. Ascaris is thought to modulate host immune and inflammatory responses, which may drive immune hyporesponsiveness during chronic infections. Using transcriptomic analysis, we show here that pigs with a chronic A. suum infection have a substantial suppression of inflammatory pathways in the intestinal mucosa, with a broad downregulation of genes encoding cytokines and antigen-processing and costimulatory molecules. A. suum body fluid (ABF) suppressed similar transcriptional pathways in human dendritic cells (DCs) in vitro. DCs exposed to ABF secreted minimal amounts of cytokines and had impaired production of cyclooxygengase-2, altered glucose metabolism, and reduced capacity to induce interferon-gamma production in T cells. Our in vivo and in vitro data provide an insight into mucosal immune modulation during Ascaris infection, and show that A. suum profoundly suppresses immune and inflammatory pathways.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/infdis/jix585DOI Listing
January 2018

Knowledge and practice on prevention of diabetes mellitus among Diabetes mellitus family members, in suburban cities in Ethiopia.

BMC Res Notes 2017 Nov 2;10(1):551. Epub 2017 Nov 2.

Department of Medical Laboratory Sciences, College of Health Science, Addis Ababa University, Addis Ababa, Ethiopia.

Background: Diabetes mellitus (DM) is one of the serious non communicable diseases worldwide. Presence of DM patient in a family may be considered as risk factor for other family members to acquire the disease, due to DM inheritance nature and/or similar life style pattern among family members. This paper assessed awareness of DM patients' family members (DMPFMs) about DM occurrence and prevention. A cross sectional study was conducted in 2014 in two suburban cities of Ethiopia, namely Kemisse, and Kombolcha using an interviewer administered questionnaire among primary or secondary degree DMPFMs and controls. Based on eligibility criteria study participants were selected by health extension workers on house to house visit. Data were analyzed using SPSS version 20, and P value less than 0.05 considered as statistically significant.

Results: Of the total 347 study participants, 45.5% (n = 158) had DMPFMs. Majority, 60.8% of DMPFMs and 73.0% of controls were males. Mean age of DMPFMs (30.06 years) was less than that of the controls (37.38 years). On living style, 51.9% DMPFMs, and 42.8% of controls were single. In both study groups, the majority of study participants attended grade 7-12. The likelihood of having good level of knowledge among DMPFMs were 2.94 times (AOR = 2.94 95% CI 1.87-4.86) higher compared to those who did not. Those attaining higher educational levels were 3.41 times (AOR = 3.41, 95% CI 1.31-8.91) more likely to have good level of knowledge, as compared to those who were unable to read and write. The likelihood of having good level of positive practice among DMPFMs were 3.38 times (AOR = 3.38% CI 2.05-5.58) higher as compared to controls. Participants who were living in Kombolcha were 2.33 times (AOR = 2.33 95% CI 1.31-4.12) more likely to have good level of practice, as compared to individuals from Kemisse.

Conclusions: Diabetes mellitus family members in the Ethiopian suburban cities Kemisse, and Kombolcha had better knowledge and practice about DM compared to controls. But, the overall awareness about DM occurrence and prevention was relatively low. Thus, DM awareness campaigns should be strongly pursued regardless of family history and educational background to prevent further increase of DM in Ethiopia.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13104-017-2871-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5669018PMC
November 2017

Helminth antigens counteract a rapid high-fat diet-induced decrease in adipose tissue eosinophils.

J Mol Endocrinol 2017 10 10;59(3):245-255. Epub 2017 Jul 10.

Department of Medical BiochemistryExperimental Vascular Biology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands

Brown adipose tissue (BAT) activation and white adipose tissue (WAT) beiging can increase energy expenditure and have the potential to reduce obesity and associated diseases. The immune system is a potential target in mediating brown and beige adipocyte activation. Type 2 and anti-inflammatory immune cells contribute to metabolic homeostasis within lean WAT, with a prominent role for eosinophils and interleukin (IL)-4-induced anti-inflammatory macrophages. We determined eosinophil numbers in epididymal WAT (EpAT), subcutaneous WAT (ScAT) and BAT after 1 day, 3 days or 1 week of high-fat diet (HFD) feeding in C57Bl/6 mice. One day of HFD resulted in a rapid drop in eosinophil numbers in EpAT and BAT, and after 3 days, in ScAT. In an attempt to restore this HFD-induced drop in adipose tissue eosinophils, we treated 1-week HFD-fed mice with helminth antigens from or and evaluated whether the well-known protective metabolic effects of helminth antigens involves BAT activation or beiging. Indeed, antigens of both helminth species induced high numbers of eosinophils in EpAT, but failed to induce beiging. In ScAT, antigens induced mild eosinophilia, which was accompanied by slightly more beiging. No effects were observed in BAT. To study type 2 responses on brown adipocytes directly, T37i cells were stimulated with IL-4. This increased expression and strongly induced the production of eosinophil chemoattractant CCL11 (+26-fold), revealing that brown adipocytes themselves can attract eosinophils. Our findings indicate that helminth antigen-induced eosinophilia fails to induce profound beiging of white adipocytes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1530/JME-17-0112DOI Listing
October 2017

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

Immunology 2017 03 30;150(3):312-328. Epub 2016 Nov 30.

Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/imm.12687DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5290246PMC
March 2017

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

FASEB J 2017 02 2;31(2):719-731. Epub 2016 Nov 2.

Department of Molecular Cell Biology and Immunology, Neuroscience Campus Amsterdam, Vrije Universiteit Medical Center Amsterdam, Amsterdam, The Netherlands;

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 worm's 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 host's 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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1096/fj.201600841RDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5240662PMC
February 2017

High-Throughput and High-Sensitivity Mass Spectrometry-Based N-Glycomics of Mammalian Cells.

Methods Mol Biol 2017 ;1503:185-196

Division of BioAnalytical Chemistry, VU University Amsterdam, De Boelelaan 1083, Amsterdam, 1081, HV, The Netherlands.

The current protocols for glycomic analysis of cells often require a large quantity of material (5-20 million cells). In order to analyze the N-glycosylation from small amounts of cells (≤1 million) as obtained from, for example, primary cell lines or cell sorting, and in a higher throughput approach, we set up a robust 96-well format PVDF-membrane based N-glycan release protocol followed by linkage-specific sialic acid stabilization, cleanup, and MALDI-TOF-MS analysis. We further evaluated the influence of PNGase F incubation time on the N-glycan profile.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/978-1-4939-6493-2_14DOI Listing
January 2018

Pleurotus citrinopileatus polysaccharide induces activation of human dendritic cells through multiple pathways.

Int Immunopharmacol 2016 Nov 1;40:156-163. Epub 2016 Sep 1.

Department of Molecular Cell Biology and Immunology, VU University Medical Center O2 Building, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands.

Many edible mushrooms have become attractive as "health foods" and as source materials for immunomodulators. To increase our insight in the immune-modulatory properties of a polysaccharide of the oyster mushroom Pleurotus citrinopileatus, PCPS, we analyzed its effects on the function of human dendritic cells (DCs). We showed that PCPS induces upregulation of the surface maturation markers CD80, CD86 and HLA-DR on DCs, indicating its potential to induce DC maturation. In addition, PCPS stimulates DCs to secrete the pro-inflammatory cytokines TNF, IL-1β, IL-6 and IL-12, as well as the anti-inflammatory cytokine IL-10, and induces enhanced mRNA levels of the chemokines CCL2, CCL3, CCL8, CXCL9, CXCL10, and LTA. The secretion of TNF and IL-12 by PCPS-activated DCs could significantly be decreased by an anti-Dectin-1 antibody, as well as by a Syk kinase and a Raf-1 inhibitor, indicating that PCPS induces Dectin-1 signaling at least partly through the Syk- and the Raf-1-dependent pathways in DCs. Structural analysis of PCPS suggests that this polysaccharide is a β-1,3-branched β-1,6-glucan, which is in line with its capacity to activate Dectin-1. We showed that PCPS can induce TLR2 and TLR4, but not TLR3, signaling using TLR-HEK293 reporter cell lines. In human DCs, the effect of PCPS was additively increased by TLR4 activation, and synergistically enhanced by stimulation of TLR2, suggesting that interaction of PCPS with these TLRs contributes to the observed DC modulation. In conclusion, PCPS has the capacity to activate human DCs via multiple pathways.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.intimp.2016.08.034DOI Listing
November 2016

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

FASEB J 2016 08 19;30(8):2826-36. Epub 2016 Apr 19.

Department of Molecular Cell Biology and Immunology, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, The Netherlands; and

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1096/fj.201600343RDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6137957PMC
August 2016

Identification of Antigenic Glycans from Schistosoma mansoni by Using a Shotgun Egg Glycan Microarray.

Infect Immun 2016 05 22;84(5):1371-1386. Epub 2016 Apr 22.

Department of Biochemistry and the Emory Glycomics Center, Emory University School of Medicine, Atlanta, Georgia, USA

Infection of mammals by the parasitic helminth Schistosoma mansoni induces antibodies to glycan antigens in worms and eggs, but the differential nature of the immune response among infected mammals is poorly understood. To better define these responses, we used a shotgun glycomics approach in which N-glycans from schistosome egg glycoproteins were prepared, derivatized, separated, and used to generate an egg shotgun glycan microarray. This array was interrogated with sera from infected mice, rhesus monkeys, and humans and with glycan-binding proteins and antibodies to gather information about the structures of antigenic glycans, which also were analyzed by mass spectrometry. A major glycan antigen targeted by IgG from different infected species is the FLDNF epitope [Fucα3GalNAcβ4(Fucα3)GlcNAc-R], which is also recognized by the IgG monoclonal antibody F2D2. The FLDNF antigen is expressed by all life stages of the parasite in mammalian hosts, and F2D2 can kill schistosomula in vitro in a complement-dependent manner. Different antisera also recognized other glycan determinants, including core β-xylose and highly fucosylated glycans. Thus, the natural shotgun glycan microarray of schistosome eggs is useful in identifying antigenic glycans and in developing new anti-glycan reagents that may have diagnostic applications and contribute to developing new vaccines against schistosomiasis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/IAI.01349-15DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4862720PMC
May 2016

Identification and functional analysis of two Golgi-localized UDP-galactofuranose transporters with overlapping functions in Aspergillus niger.

BMC Microbiol 2015 Nov 2;15:253. Epub 2015 Nov 2.

Leiden University, Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Sylviusweg 72, 2333 BE, Leiden, The Netherlands.

Background: Galactofuranose (Galf)-containing glycoconjugates are present in numerous microbes, including filamentous fungi where they are important for morphology, virulence and maintaining cell wall integrity. The incorporation of Galf-residues into galactomannan, galactomannoproteins and glycolipids is carried out by Golgi-localized Galf transferases. The nucleotide sugar donor used by these transferases (UDP-Galf) is produced in the cytoplasm and has to be transported to the lumen of the Golgi by a dedicated nucleotide sugar transporter.

Methods: Based on homology with recently identified UDP-Galf-transporters in A. fumigatus and A. nidulans, two putative UDP-Galf-transporters in A. niger were found. Their function and localization was determined by gene deletions and GFP-tagging studies, respectively.

Results: The two putative UDP-Galf-transporters in A. niger are homologous to each other and are predicted to contain eleven transmembrane domains (UgtA) or ten transmembrane domains (UgtB) due to a reduced length of the C-terminal part of the UgtB protein. The presence of two putative UDP-Galf-transporters in the genome was not unique for A. niger. From the twenty Aspergillus species analysed, nine species contained two additional putative UDP-Galf-transporters. Three of the nine species were outside the Aspergillus section nigri, indication an early duplication of UDP-Galf-transporters and subsequent loss of the UgtB copy in several aspergilli. Deletion analysis of the single and double mutants in A. niger indicated that the two putative UDP-Galf-transporters (named UgtA and UgtB) have a redundant function in UDP-Galf-transport as only the double mutant displayed a Galf-negative phenotype. The Galf-negative phenotype of the double mutant could be complemented by expressing either CFP-UgtA or CFP-UgtB fusion proteins from their endogenous promoters, indicating that both CFP-tagged proteins are functional. Both Ugt proteins co-localize with each other as well as with the GDP-mannose nucleotide transporter, as was demonstrated by fluorescence microscopy, thereby confirming their predicted localization in the Golgi.

Conclusion: A. niger contains two genes encoding UDP-Galf-transporters. Deletion and localization studies indicate that UgtA and UgtB have redundant functions in the biosynthesis of Galf-containing glycoconjugates.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12866-015-0541-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4630932PMC
November 2015

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

FEBS Lett 2015 Aug 29;589(18):2359-66. Epub 2015 Jul 29.

Department of Molecular Cell Biology and Immunology, VU University Medical Center, 1007 MB Amsterdam, The Netherlands. Electronic address:

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.febslet.2015.07.035DOI Listing
August 2015

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

Acta Neuropathol Commun 2015 Jul 25;3:45. Epub 2015 Jul 25.

Department of Molecular Cell Biology and Immunology, Neuroscience Campus Amsterdam, VU University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands.

Introduction: The 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.

Results: Here 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.

Conclusion: This study provides comprehensive mechanistic insight into helminth-induced immunomodulation, which can be therapeutically exploited to combat various auto-immune disorders.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s40478-015-0223-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4513676PMC
July 2015

Promoters of Human Cosmc and T-synthase Genes Are Similar in Structure, Yet Different in Epigenetic Regulation.

J Biol Chem 2015 Jul 10;290(31):19018-33. Epub 2015 Jun 10.

From the Departments of Biochemistry,

The T-synthase (core 1 β3-galactosyltransferase) and its molecular chaperone Cosmc regulate the biosynthesis of mucin type O-glycans on glycoproteins, and evidence suggests that both T-synthase and Cosmc are transcriptionally suppressed in several human diseases, although the transcriptional regulation of these two genes is not understood. Here, we characterized the promoters essential for human Cosmc and T-synthase transcription. The upstream regions of the genes lack a conventional TATA box but contain CpG islands, cCpG-I and cCpG-II for Cosmc and tCpG for T-synthase. Using luciferase reporter assays, site-directed mutagenesis, ChIP assays, and mithramycin A treatment, we identified the core promoters within cCpG-II and tCpG, which contain two binding sites for Krüppel-like transcription factors, including SP1/SP3, respectively. Methylome analysis of Tn4 B cells, which harbor a silenced Cosmc, confirmed the hypermethylation of the Cosmc core promoter but not for T-synthase. These results demonstrate that Cosmc and T-synthase are transcriptionally regulated at a basal level by the specificity protein/Krüppel-like transcription factor family of members, which explains their ubiquitous and coordinated expression, and also indicate that they are differentially epigenetically regulated beyond X chromosome imprinting. These results are important in understanding the regulation of these genes that have roles in human diseases, such as IgA nephropathy and cancer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.M115.654244DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4521027PMC
July 2015

Schistosoma mansoni Soluble Egg Antigens Induce Expression of the Negative Regulators SOCS1 and SHP1 in Human Dendritic Cells via Interaction with the Mannose Receptor.

PLoS One 2015 21;10(4):e0124089. Epub 2015 Apr 21.

Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, The Netherlands.

Schistosomiasis is a common debilitating human parasitic disease in (sub)tropical areas, however, schistosome infections can also protect against a variety of inflammatory diseases. This has raised broad interest in the mechanisms by which Schistosoma modulate the immune system into an anti-inflammatory and regulatory state. Human dendritic cells (DCs) show many phenotypic changes upon contact with Schistosoma mansoni soluble egg antigens (SEA). We here show that oxidation of SEA glycans, but not heat-denaturation, abrogates the capacity of SEA to suppress both LPS-induced cytokine secretion and DC proliferation, indicating an important role of SEA glycans in these processes. Remarkably, interaction of SEA glycans with DCs results in a strongly increased expression of Suppressor Of Cytokine Signalling1 (SOCS1) and SH2-containing protein tyrosine Phosphatase-1 (SHP1), important negative regulators of TLR4 signalling. In addition, SEA induces the secretion of transforming growth factor β (TGF-β), and the surface expression of the costimulatory molecules Programmed Death Ligand-1 (PD-L1) and OX40 ligand (OX40L), which are known phenotypic markers for the capacity of DCs to polarize naïve T cells into Th2/Treg cell subsets. Inhibition of mannose receptor (MR)-mediated internalization of SEA into DCs by blocking with allyl α-D-mannoside or anti-MR antibodies, significantly reduced SOCS1 and SHP1 expression. In conclusion, we demonstrate that SEA glycans are essential for induction of enhanced SOCS1 and SHP1 levels in DCs via the MR. Our data provide novel mechanistic evidence for the potential of S. mansoni SEA glycans to modulate human DCs, which may contribute to the capacity of SEA to down-regulate inflammatory responses.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0124089PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4405200PMC
April 2016

Identification of the UDP-glucose-4-epimerase required for galactofuranose biosynthesis and galactose metabolism in .

Fungal Biol Biotechnol 2014 14;1. Epub 2014 Oct 14.

Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, Leiden, 2333 BE The Netherlands.

Background: Galactofuranose (Gal)-containing glycoconjugates are important to secure the integrity of the cell wall of filamentous fungi. Mutations that prevent the biosynthesis of Gal-containing molecules compromise cell wall integrity. In response to cell wall weakening, the cell wall integrity (CWI)-pathway is activated to reinforce the strength of the cell wall. Activation of CWI-pathway in is characterized by the specific induction of the gene, which encodes a cell wall α-glucan synthase.

Results: In this study, we screened a collection of cell wall mutants with an induced expression of for defects in Gal biosynthesis using a with anti-Gal antibody (L10). From this collection of mutants, we previously identified mutants in the UDP-galactopyranose mutase encoding gene (). Here, we have identified six additional UDP-galactopyranose mutase () mutants and one mutant (named mutant #41) in an additional complementation group that displayed strongly reduced Gal-levels in the cell wall. By using a whole genome sequencing approach, 21 SNPs in coding regions were identified between mutant #41 and its parental strain which changed the amino acid sequence of the encoded proteins. One of these mutations was in gene An14g03820, which codes for a putative UDP-glucose-4-epimerase (UgeA). The A to G mutation in this gene causes an amino acid change of Asn to Asp at position 191 in the UgeA protein. Targeted deletion of resulted in an even more severe reduction of Gal in N-linked glucans, indicating that the UgeA protein in mutant #41 is partially active. The gene is also required for growth on galactose despite the presence of two UgeA homologs in the genome.

Conclusion: By using a classical mutant screen and whole genome sequencing of a new Gal-deficient mutant, the UDP-glucose-4-epimerase gene () has been identified. UgeA is required for the biosynthesis of Gal as well as for galactose metabolism in .
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s40694-014-0006-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5598270PMC
October 2014

Fucose-based PAMPs prime dendritic cells for follicular T helper cell polarization via DC-SIGN-dependent IL-27 production.

Nat Commun 2014 Oct 3;5:5074. Epub 2014 Oct 3.

Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam,The Netherlands.

Dendritic cells (DCs) orchestrate antibody-mediated responses to combat extracellular pathogens including parasites by initiating T helper cell differentiation. Here we demonstrate that carbohydrate-specific signalling by DC-SIGN drives follicular T helper cell (TFH) differentiation via IL-27 expression. Fucose, but not mannose, engagement of DC-SIGN results in activation of IKKε, which collaborates with type I IFNR signalling to induce formation and activation of transcription factor ISGF3. Notably, ISGF3 induces expression of IL-27 subunit p28, and subsequent IL-27 secreted by DC-SIGN-primed DCs is pivotal for the induction of Bcl-6(+)CXCR5(+)PD-1(hi)Foxp1(lo) TFH cells, IL-21 secretion by TFH cells and T-cell-dependent IgG production by B cells. Thus, we have identified an essential role for DC-SIGN-induced ISGF3 by fucose-based PAMPs in driving IL-27 and subsequent TFH polarization, which might be harnessed for vaccination design.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/ncomms6074DOI Listing
October 2014

Identification of distinct glycoforms of IgA1 in plasma from patients with immunoglobulin A (IgA) nephropathy and healthy individuals.

Mol Cell Proteomics 2014 Nov 28;13(11):3097-113. Epub 2014 Jul 28.

From the Departments of ‡Biochemistry and

Immunoglobulin A nephropathy (IgAN) is the most common form of glomerulonephritis worldwide and is histologically characterized by the deposition of IgA1 and consequent inflammation in the glomerular mesangium. Prior studies suggested that serum IgA1 from IgAN patients contains aberrant, undergalactosylated O-glycans, for example, Tn antigen and its sialylated version, SialylTn (STn), but the mechanisms underlying aberrant O-glycosylation are not well understood. Here we have used serial lectin separation technologies, Western blot, enzymatic modifications, and mass spectrometry to explore whether there are different glycoforms of IgA1 in plasma from patients with IgAN and healthy individuals. Although total plasma IgA in IgAN patients was elevated ∼ 1.6-fold compared with that in healthy donors, IgA1 in all samples was unexpectedly separable into two distinct glycoforms: one with core 1 based O-glycans, and the other exclusively containing Tn/STn structures. Importantly, Tn antigen present on IgA1 from IgAN patients and controls was convertible into the core 1 structure in vitro by recombinant T-synthase. Our results demonstrate that undergalactosylation of O-glycans in IgA1 is not restricted to IgAN and suggest that in vivo inefficiency of T-synthase toward IgA1 in a subpopulation of B or plasma cells, as well as overall elevation of IgA, may contribute to IgAN pathogenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/mcp.M114.039693DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4223494PMC
November 2014

Galectin-4 expression is associated with reduced lymph node metastasis and modulation of Wnt/β-catenin signalling in pancreatic adenocarcinoma.

Oncotarget 2014 Jul;5(14):5335-49

Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, The Netherlands.

Galectin-4 (Gal-4) has been recently identified as a pivotal factor in the migratory capabilities of a set of defined pancreatic ductal adenocarcinoma (PDAC) cell lines using zebrafish as a model system. Here we evaluated the expression of Gal-4 in PDAC tissues selected according to their lymph node metastatic status (N0 vs. N1), and investigated the therapeutic potential of targeting the cross-link with the Wnt signaling pathway in primary PDAC cells. Analysis of Gal-4 expression in PDACs showed high expression of Gal-4 in 80% of patients without lymph node metastasis, whereas 70% of patients with lymph node metastases had low Gal-4 expression. Accordingly, in primary PDAC cells high Gal-4 expression was negatively associated with migratory and invasive ability in vitro and in vivo. Knockdown of Gal-4 in primary PDAC cells with high Gal-4 expression resulted in significant increase of invasion (40%) and migration (50%, P<0.05), whereas enforced expression of Gal-4 in primary cells with low Gal-4 expression reduced the migratory and invasive behavior compared to the control cells. Gal-4 markedly reduces β-catenin levels in the cell, counteracting the function of Wnt signaling, as was assessed by down-regulation of survivin and cyclin D1. Furthermore, Gal-4 sensitizes PDAC cells to the Wnt inhibitor ICG-001, which interferes with the interaction between CREB binding protein (CBP) and β-catenin. Collectively, our data suggest that Gal-4 lowers the levels of cytoplasmic β-catenin, which may lead to lowered availability of nuclear β-catenin, and consequently diminished levels of nuclear CBP-β-catenin complex and reduced activation of the Wnt target genes. Our findings provide novel insights into the role of Gal-4 in PDAC migration and invasion, and support the analysis of Gal-4 for rational targeting of Wnt/β-catenin signaling in the treatment of PDAC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.18632/oncotarget.2104DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4170638PMC
July 2014

Deletion of the CAP10 gene of Cryptococcus neoformans results in a pleiotropic phenotype with changes in expression of virulence factors.

Res Microbiol 2014 Jul-Aug;165(6):399-410. Epub 2014 Apr 19.

Microbiology, Institute of Biomembranes, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands. Electronic address:

The human pathogen Cryptococcus neoformans causes meningo-encephalitis. The polysaccharide capsule is an important virulence factor for this yeast-like fungus. Previously, we had shown that disruption of the CAP10 gene, encoding a putative xylosyltransferase, results in mutant cells that lack most of the capsular polysaccharides on the cell surface, but do not show a typical acapsular phenotype. In contrast to the acapsular cap59 mutant, cap10 did not induce maturation of dendritic cells when exposed to components of the immune system. In order to gain further insight into the causes of this phenotype displayed by the cap10 mutant, we performed a more in-depth phenotypic analysis of the cell wall and surface structures of this mutant compared to the wild type strain and acapsular mutant cap59. Moreover, we analyzed the cap10 mutant and the wild type strain for differential gene expression of, amongst others, enzymes that are involved in biogenesis of cell wall and capsule components. We conclude that a mutation in the CAP10 gene results in a pleiotropic phenotype with effects on different cellular processes affecting, amongst others, cell size, expression of virulence factors and size of extracellular vesicles.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.resmic.2014.04.001DOI Listing
March 2015

Differential expression of anti-glycan antibodies in schistosome-infected humans, rhesus monkeys and mice.

Glycobiology 2014 Jul 11;24(7):602-18. Epub 2014 Apr 11.

Department of Biochemistry, Emory University School of Medicine, O. Wayne Rollins Research Center, 1510 Clifton Road, Suite 4001, Atlanta, GA 30322, USA

Schistosomiasis is a debilitating parasitic disease of humans, endemic in tropical areas, for which no vaccine is available. Evidence points to glycan antigens as being important in immune responses to infection. Here we describe our studies on the comparative humoral immune responses to defined schistosome-type glycan epitopes in Schistosoma mansoni-infected humans, rhesus monkeys and mice. Rhesus anti-glycan responses over the course of infection were screened on a defined glycan microarray comprising semi-synthetic glycopeptides terminating with schistosome-associated or control mammalian-type glycan epitopes, as well as a defined glycan microarray of mammalian-type glycans representing over 400 glycan structures. Infected rhesus monkeys generated a high immunoglobulin G (IgG) antibody response to the core xylose/core α3 fucose epitope of N-glycans, which peaked at 8-11 weeks post infection, coinciding with maximal ability to kill schistosomula in vitro. By contrast, infected humans generated low antibody levels to this epitope. At 18 months following praziquantel therapy to eliminate the parasite, antibody levels were negligible. Mice chronically infected with S. mansoni generated high levels of anti-fucosylated LacdiNAc (GalNAcβ1, 4(Fucα1, 3)GlcNAc) IgM antibodies, but lacked a robust response to the core xylose/core α3 fucose N-glycan antigens compared with other species studied, and their sera demonstrated an intermediate level of schistosomula killing in vitro. These differential responses to parasite glycan antigens may be related to the ability of rhesus monkeys to self-cure in contrast to the chronic infection seen in humans and mice. Our results validate defined glycan microarrays as a useful technology to evaluate diagnostic and vaccine antigens for schistosomiasis and perhaps other infections.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/glycob/cwu029DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4038252PMC
July 2014

Galactofuranose-coated gold nanoparticles elicit a pro-inflammatory response in human monocyte-derived dendritic cells and are recognized by DC-SIGN.

ACS Chem Biol 2014 Feb 9;9(2):383-9. Epub 2013 Dec 9.

Laboratory of GlycoNanotechnology, Biofunctional Nanomaterials Unit, CIC biomaGUNE, Paseo Miramón 182, 20009, San Sebastián, Spain.

Galactofuranose (Galf) is the five-membered ring form of galactose exclusively found in nonmammalian species, among which several are pathogens. To determine the putative role of this carbohydrate in host-pathogen interactions, we synthesized multivalent gold nanoparticles carrying Galf (Galf-GNPs) and show that they are recognized by the EB-A2 antibody, which is widely used to detect Galf-containing galactomannan in the serum of Aspergillosis patients. We demonstrated that human monocyte-derived dendritic cells bound Galf-GNPs via interaction with the lectin DC-SIGN. Moreover, interaction of dendritic cells with Galf-GNPs resulted in increased expression of several maturation markers on these cells and induced secretion of the pro-inflammatory cytokines IL-6 and TNF-α. These data indicate that Galf is able to modulate the innate immune response via dendritic cells. In conclusion, Galf-GNPs are a versatile tool that can be applied in multiple functional studies to gain a better understanding of the role of Galf in host-pathogen interaction.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/cb4008265DOI Listing
February 2014
-->