Biology subjects

Madunic, K.

Publications and source records attributed to Madunic, K..

3 recordsLinked to original sources

bioRxiv2021

Dissection of N-, O- and glycosphingolipid glycosylation changes in PaTu-S pancreatic adenocarcinoma cells upon TGF-β challenge

Pancreatic ductal adenocarcinoma (PDAC) is characterized by poor prognosis and high mortality. Transforming growth factor-{beta} (TGF-{beta}) plays a key role in tumor progression, which is often associated with aberrant glycosylation. How PDAC cells respond to TGF-{beta} and the role of glycosylation therein is, however, not well known. Here, we investigated the TGF-{beta}-mediated response and glycosylation changes in SMAD4-deficient PaTu-8955S (PaTu-S) cell line. PaTu-S cells responded to TGF-{beta} by upregulating SMAD2 phosphorylation and target gene expression. TGF-{beta} induced expression of the mesenchymal marker N-cadherin, but did not significantly affect epithelial marker E-cadherin expression. The differences of N-glycans, O-glycans and glycosphingolipid (GSL) glycans in PaTu-S cells with TGF-{beta} stimulation were examined. TGF-{beta} treatment primarily induced N-glycome aberrations involving elevated levels of branching, core fucosylation, and sialylation in PaTu-S cells, in line with TGF-{beta}-induced changes in the expression of glycosylation-related genes. In addition, we observed differences in O- and GSL-glycosylation profiles after TGF-{beta} treatment, including lower levels of sialylated Tn antigen, and neoexpression of globosides. Furthermore, SOX4 expression was upregulated upon TGF-{beta} stimulation, and its depletion blocked the TGF-{beta}-induced N-glycomic changes. Thus, our study provides a mechanism by which TGF-{beta}-induced N-glycosylation changes in SOX4 dependent and SMAD4 independent manner in pancreatic cancer cells. Our results open up avenues to study the relevance of glycosylation in TGF-{beta} signaling in SMAD4 inactivated PDAC.

cancer biology↗

bioRxiv2019

Prominent members of the human gut microbiota express endo-acting O-glycanases to initiate mucin breakdown

The human gut microbiota (HGM) are closely associated with health, development and disease. The thick intestinal mucus layer, especially in the colon, is the key barrier between the contents of the lumen and the epithelial cells, providing protection against infiltration by the microbiota as well potential pathogens. The upper layer of the colonic mucus is a niche for a subset of the microbiota which utilise the mucin glycoproteins as a nutrient source and mucin grazing by the microbiota appears to play a key role in maintaining barrier function as well as community stability. Despite the importance of mucin breakdown for gut health, the mechanisms by which gut bacteria access this complex glycoprotein are not well understood. The current model for mucin degradation involves exclusively exo-acting glycosidases that sequentially trim monosaccharides from the termini of the glycan chains to eventually allow access to the mucin peptide backbone by proteases. However, this model is in direct contrast to the Sus paradigm of glycan breakdown used by the Bacteroidetes which involves extracellular cleavage of glycans by surface located endo-acting enzymes prior to import of the oligosaccharide products. Here we describe the discovery and characterisation of endo-acting family 16 glycoside hydrolases (GH16s) from prominent mucin degrading gut bacteria that specifically target the oligosaccharide side chains of intestinal mucins from both animals and humans. These endo-acting O-glycanases display {beta}1,4-glactosidase activity and in several cases are surface located indicating they are involved in the initial step in mucin breakdown. The data suggest a new paradigm for mucin breakdown by the microbiota and the endo-mucinases provide a potential tool to explore changes that occur in mucin structure in intestinal disorders such as inflammatory bowel disease and colon cancer.

biochemistry↗

bioRxiv2018

e-workflow for recording of glycomic mass spectrometric data in compliance with reporting guidelines

Glycomics targets released glycans from proteins, lipids and proteoglycans. High throughput glycomics is based on mass spectrometry (MS) that increasingly depends on exchange of data with databases and the use of software. This requires an agreed format for accurately recording of experiments, developing consistent storage modules and granting public access to glycomic MS data. The introduction of the MIRAGE (Mimimum Requirement for A Glycomics Experiment) reporting standards for glycomics was the first step towards automating glycomic data recording. This report describes a glycomic e-infrastructure utilizing a well established glycomics recording format (GlycoWorkbench), and a dedicated web tool for submitting MIRAGE-compatible MS information into a public experimental repository, UniCarb-DR. The submission of data to UniCarb-DR should be a part of the submission process for publications with glycomics MSn that conform to the MIRAGE guidelines. The structure of this pipeline allows submission of most MS workflows used in glycomics.

bioinformatics↗