Biology subjects

Pomin, V. H.

Publications and source records attributed to Pomin, V. H..

4 recordsLinked to original sources

bioRxiv2026

Marine sulfated glycans inhibit the binding of Borrelia burgdorferi adhesins to heparin/GAGs

Recognition of host glycosaminoglycans (GAGs) is critical for the adhesion and colonization of Borrelia burgdorferi, but the structural requirements for these interactions remain incompletely understood. Using surface plasmon resonance (SPR), we characterized the heparin-binding properties of three Borrelia adhesins, i.e. Bgp, DbpA-A9, and DbpB-B31 and evaluated inhibitors comprising heparin oligosaccharides, selectively desulfated heparins, mammalian GAGs, marine sulfated glycans, pentosan polysulfate (PPS), and mucopolysaccharide polysulfate (MPS). All three adhesins bound directly to heparin, with equilibrium dissociation constants (KD) of 2.18 nM for Bgp and 36.4 nM for DbpB-B31. Competition assays identified N-sulfation and 6-O-sulfation as major determinants of binding, whereas 2-O-sulfation had a lower effect. Bgp showed chain-length dependence over dp4-dp20, whereas DbpB-B31 preferentially recognized longer oligosaccharides, particularly those of dp12 or greater. Chondroitin sulfate E also exhibited strong inhibitory activity, indicating that recognition was not restricted to heparin/heparan sulfate backbones. Among the tested sulfated glycans, fucosylated chondroitin sulfate (HfFucCS) from Holothuria floridana was the most potent inhibitor of Bgp, with an IC50 of approximately 4 ng/mL, whereas PPS was the strongest inhibitor of DbpB-B31, followed by MPS. These findings reveal protein-specific sulfated-glycan recognition and identify promising candidates for disrupting B. burgdorferi-host GAG interactions.

biochemistry↗

bioRxiv2023

Heparan-6-O-endosulfatase 2 promotes invasiveness of head and neck squamous carcinoma cell lines in co-cultures with cancer associated fibroblasts

Local invasiveness of head and neck squamous cell carcinoma (HNSCC) is a complex phenomenon supported by interaction of the cancer cells with the TME. We and others have shown that CAFs are a component of the TME that can promote local invasion in HNSCC and other cancers. Here we report that the secretory enzyme Sulf-2 directly affects the CAF-supported invasion of HNSCC cell lines SCC35 and Cal33 into Matrigel. The Sulf-2 knockout (KO) cells differ from their wild type counterparts in their spheroid growths and formation, and the Sulf-2-KO leads to decreased invasion in a spheroid co-culture model with the CAF. Next, we investigated whether a fucosylated chondroitin sulfate isolated from the sea cucumber Holothuria Floridana (HfFucCS), affects activity of the Sulf-2 enzyme. Our results show that HfFucCS not only inhibits efficiently the Sulf-2 enzymatic activity but, like the Sulf-2 knockout, inhibits Matrigel invasion of the SCC35 and Cal33 cells co-cultured with the primary HNSCC CAF. These findings suggest that the heparan 6-O-endosulfatases regulate local invasion and could be therapeutically targeted with the inhibitory activity of a marine glycosaminoglycan. Simple SummaryLocal invasion of cancer cells is an early step in the cascade of metastasis that requires cooperation of multiple factors and cell types in the tumor microenvironment (TME). One important factor is the crosstalk of cancer cells with cancer associated fibroblasts (CAF). Here we explore the impact of a secretory enzyme heparan-6-O-endosulfatase 2 (Sulf-2) on the CAF-assisted invasion of head and neck squamous carcinoma cells into matrigel. We show that Sulf-2 knock out inhibits cancer cell invasion in a spheroid co-culture model and we identified a novel Sulf-2 inhibitor that, in the same model, limits cancer cell invasion.

cancer biology↗

bioRxiv2020

Effective Inhibition of SARS-CoV-2 Entry by Heparin and Enoxaparin Derivatives

Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) has caused a pandemic of historic proportions and continues to spread globally, with enormous consequences to human health. Currently there is no vaccine, effective therapeutic or prophylactic. Like other betacoronaviruses, attachment and entry of SARS-CoV-2 is mediated by the spike glycoprotein (SGP). In addition to its well-documented interaction with its receptor, human angiotensin converting enzyme 2 (hACE2), SGP has been found to bind to glycosaminoglycans like heparan sulfate, which is found on the surface of virtually all mammalian cells. Here, we pseudotyped SARS-CoV-2 SGP on a third generation lentiviral (pLV) vector and tested the impact of various sulfated polysaccharides on transduction efficiency in mammalian cells. The pLV vector pseudotyped SGP efficiently and produced high titers on HEK293T cells. Various sulfated polysaccharides potently neutralized pLV-S pseudotyped virus with clear structure-based differences in anti-viral activity and affinity to SGP. Concentration-response curves showed that pLV-S particles were efficiently neutralized by a range of concentrations of unfractionated heparin (UFH), enoxaparin, 6-O-desulfated UFH and 6-O-desulfated enoxaparin with an IC50 of 5.99 {micro}g/L, 1.08 mg/L, 1.77 {micro}g/L, and 5.86 mg/L respectively. The low serum bioavailability of intranasally administered UFH, along with data suggesting that the nasal epithelium is a portal for initial infection and transmission, suggest that intranasal administration of UFH may be an effective and safe prophylactic treatment.

microbiology↗

bioRxiv2017

Mapping of the Fondaparinux Binding Site of JR-FL gp120 by High Resolution Hydroxyl Radical Protein Footprinting and Computational Docking

The adhesion of HIV gp120 antigen to human cells is modulated in part by interactions with heparan sulfate. The HXB2 strain of gp120 has been shown to interact with heparin primarily through the V3 loop, although other domains including the C-terminal domain were also implicated. However, the JR-FL strain (representative of CCR5-interacting strains that make up newest infections) was shown to have a drastically lowered affinity to heparin due to the loss of several basic residues in the V3 loop, and deletion of the V3 loop in JR-FL gp120 was shown to abrogate some, but not all, heparin binding. Here, we use high resolution hydroxyl radical protein footprinting to measure the changes in protein surface oxidation levels that result from the binding of a model heparin fragment (fondaparinux). Protection in both the V3 loop and the N-terminus of JR-FP gp120 is observed. The well-defined composition of fondaparinux allowed us to perform docking simulations, which showed two clusters of fondaparinux binding: the V3 loop, and a domain consisting of the N- and C-termini. Together, the experimental and theoretical results indicate the heparin/heparan sulfate binding sites on JR-FL gp120 and the efficient interaction of fondaparinux, a widely exploited therapeutic carbohydrate, on gp120.

biochemistry↗