Biology subjects

Gordts, P. L. S. M.

Publications and source records attributed to Gordts, P. L. S. M..

3 recordsLinked to original sources

bioRxiv2022

Biologically-derived neoproteoglycans for profiling protein-glycosaminoglycan interactions

Glycosaminoglycans (GAGs) are a class of highly negatively charged membrane associated and extracellular matrix polysaccharides involved in the regulation of myriad biological functions, including cell adhesion, migration, signaling and differentiation, among others. GAGs are typically attached to core proteins, termed proteoglycans (PGs), and can engage >500 binding proteins, making them prominent relays for sensing external stimuli and transducing cellular responses. However, their unique substructural protein-recognition domains that confer their binding specificity remain elusive. While the emergence of glycan arrays has rapidly enabled the profiling of ligand specificities of a range of glycan-binding proteins, their adaptation for the analysis of GAG-binding proteins has been considerably more challenging. Current GAG-microarrays primarily employ synthetically defined oligosaccharides, which capture only a fraction of the structural diversity of native GAG polysaccharides. Augmenting existing array platforms to include GAG structures purified from tissues or produced in cells with engineered glycan biosynthetic pathways may significantly advance the understanding of structure-activity relationships in GAG-protein interactions. Here, we demonstrate an efficient and tunable strategy to mimic cellular proteoglycan architectures by conjugating biologically-derived GAG chains to a protein scaffold, defined as neoproteoglycans (neoPGs). The use of a reactive fluorogenic linker enabled real-time monitoring of the conjugation reaction efficiency and tuning of the neoPG valency. Immobilization of the reagents on a 96-well array platform allowed for efficient probing of ligand binding and enzyme substrate specificity, including growth factors and the human sulfatase 1. The neoPGs can also be used directly as soluble probes to evaluate GAG-dependent growth factor signaling in cells. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=92 SRC="FIGDIR/small/482917v1_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@1a51f0org.highwire.dtl.DTLVardef@1f99e16org.highwire.dtl.DTLVardef@f9c5b9org.highwire.dtl.DTLVardef@242d9a_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2021

The Human Milk Oligosaccharide 3-Sialyllactose Promotes Inflammation Resolution and Reduces Atherosclerosis Development in Mice.

Macrophages contribute to the induction and resolution of inflammation and play a central role in the chronic low-grade inflammation in cardiovascular diseases caused by atherosclerosis. Human milk oligosaccharides (HMOs) are complex unconjugated glycans unique to human milk that benefit infant health and act as innate immune modulators. Here, we identify the HMO 3sialyllactose (3SL) as a natural inhibitor of TLR4-induced low-grade inflammation in macrophages and endothelium. Transcriptome analysis in macrophages revealed that 3SL attenuates a selected set of inflammatory gene expression and promotes activity of LXR and SREBP. These acute anti-inflammatory effects of 3SL were associated with reduced histone H3K27 acetylation at a subset of LPS-inducible enhancers distinguished by preferential enrichment for CTCF, IRF2, BCL6, and other transcription factor recognition motifs. In a murine atherosclerosis model, both subcutaneous and oral administration of 3SL significantly reduced atherosclerosis development and the associated inflammation. This study provides evidence that 3SL attenuates inflammation by a transcriptional mechanism to reduce atherosclerosis development in the context of cardiovascular disease.

immunology↗

bioRxiv2020

SARS-CoV-2 Infection Depends on Cellular Heparan Sulfate and ACE2

We show that SARS-CoV-2 spike protein interacts with cell surface heparan sulfate and angiotensin converting enzyme 2 (ACE2) through its Receptor Binding Domain. Docking studies suggest a putative heparin/heparan sulfate-binding site adjacent to the domain that binds to ACE2. In vitro, binding of ACE2 and heparin to spike protein ectodomains occurs independently and a ternary complex can be generated using heparin as a template. Contrary to studies with purified components, spike protein binding to heparan sulfate and ACE2 on cells occurs codependently. Unfractionated heparin, non-anticoagulant heparin, treatment with heparin lyases, and purified lung heparan sulfate potently block spike protein binding and infection by spike protein-pseudotyped virus and SARS-CoV-2 virus. These findings support a model for SARS-CoV-2 infection in which viral attachment and infection involves formation of a complex between heparan sulfate and ACE2. Manipulation of heparan sulfate or inhibition of viral adhesion by exogenous heparin may represent new therapeutic opportunities.

microbiology↗