Sulfation Patterns Research Articles

Chemical Approaches to Prepare Modified Heparin and Heparosan Polymers for Biological Studies.

Heparin is a potent clinically used anticoagulant. It is a heterogeneous mixture of polymers that contain a variety of sulfation patterns. Heparin polymers carrying rare 3-O-sulfated glucosamine units have been proven to be critical for binding to antithrombin and elicit an anticoagulant response. Heparins with other sulfation patterns are able to bind to a variety of other proteins such as FGF, VEGF, and CXCL-3. By modulating heparin's sulfation pattern, it is possible to generate polymers that can regulate biological processes beyond hemostasis. In this chapter, we describe a variety of chemical modification methods, including N-acetylation, N-deacetylation, N-sulfation, O-sulfation, selective 2-O desulfation, and complete desulfation, to prepare heparin-like polymers with distinct sulfation patterns for conducting biological studies.

Automated Synthesis of Chondroitin Sulfate Oligosaccharides.

Glycosaminoglycans (GAGs) are important sulfated carbohydrates prevalently found in the extracellular matrix that serve many biological functions. The synthesis of structurally diverse but defined GAGs is extremely challenging as one has to account for the various sulfation patterns. Described is the automated synthesis of chondroitin sulfate hexasaccharides on a solid support equipped with a photolabile linker. The linker cleavage from the resin is performed in a continuous-flow photoreactor under chemically mild conditions. This approach serves as a general scheme to access oligosaccharides of all GAG families.

Nuclear Magnetic Resonance Methods in Structural Characterization of Glycosaminoglycans.

Glycosaminoglycans (GAGs) are sulfated glycans of complex structure and multiple biological actions. They are composed of disaccharide repeating units of alternating uronic acid/galactose and hexosamine. Sulfation patterns are an additional structural variation of these polymers. Nuclear magnetic resonance (NMR) spectroscopy is one of the most powerful analytical techniques employed in structural analysis of GAGs. 1D and 2D NMR spectra, both homonuclear 1H and heteronuclear 1H-13C, are the commonest NMR methods used. This chapter describes the overall experimental methods and materials necessary for adequate preparation of GAG samples for NMR investigations aimed to unveil the main structural characteristics of these biomacromolecules. The NMR methods discussed here cover all three isotopes (1H, 13C, and 15N) that can be exploited in structural analysis of GAGs. These NMR methods are described from an overall standpoint, to be applied to any GAG family, extracted from either natural or synthetic sources and destined to either basic research or pharmaceutical applications.

OC15.07: Distinctive endothelial and angiogenic signature of pre‐eclampsia versus COVID‐19 in pregnancy

To study endothelial damage, microvascular thrombosis, immune response and angiogenic imbalance in pre-eclampsia (PE) and COVID-19 in pregnancy. Plasma and sera samples were obtained from pregnant women with COVID-19 infection classified into mild (n=10) or severe (n=9) in addition to normotensive pregnancies as controls (n=10) and patients with PE (n=13). Biomarker assessment included circulating VCAM-1, TNF-receptor I (TNFRI), angiotensin II (ANGII), heparan sulfate (HS), thrombomodulin (TM), VWF antigen, activity and multimeric pattern, α2-antiplasmin (α2AP), dsDNA for neutrophil extracellular traps (NETs), C5b9, PAI-1, ADAMTS-13 activity, fms-like tyrosine kinase-1 (sFlt1) and placental growth factor (PlGF). Statistical analysis included univariate and multivariate methods. Both COVID-19 and PE showed abnormal results in most endotheliopathy and immune response markers, with distinctive profiles among them: severe COVID-19 with predominant alterations in HS, NETS and PlGF, versus PE with most significant alterations in VCAM-1, TNFRI, ANGII, VWF, PAI, c5b9 and sFlt1. The principal component analysis (figure 1) demonstrated a clear separation between PE and the rest of groups (first and second components explained 42.2% and 13.5% of the variance), mainly differentiated by variables related to VWF that were markedly reduced in PE. COVID-19 and PE exhibit distinctive profiles of endothelial damage, immune dysregulation and angiogenic imbalance, which could help in the differential diagnosis and development of new therapeutic strategies. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Sulfation Code and Conformational Plasticity of l-Iduronic Acid Homo-Oligosaccharides Mimic the Biological Functions of Heparan Sulfate.

Recently, the activity of heparan sulfate (HS) has led to the discovery of many drug candidates that have the potential to impact both medical science and human health. However, structural diversity and synthetic challenges impede the progress of HS research. Here, we report a library of novel l-iduronic acid (IdoA)-based HS mimics that are highly tunable in conformation plasticity and sulfation patterns to produce many of the functions of native HS oligosaccharides. The NMR analysis of HS mimics confirmed that 4-O-sulfation enhances the population of the 1C4 geometry. Interestingly, the 1C4 conformer becomes exclusive upon additional 2-O-sulfation. HS mimic microarray binding studies with different growth factors showed that selectivity and avidity are greatly modulated by the oligosaccharide length, sulfation code, and IdoA conformation. Particularly, we have identified 4-O-sulfated IdoA disaccharide (I-21) as a potential ligand for vascular endothelial growth factor (VEGF165), which in a multivalent display modulated endothelial cell proliferation, migration, and angiogenesis. Overall, these results encourage the consideration of HS mimics for therapeutic applications.

Changes of precipitation acidity related to sulfur and nitrogen deposition in forests across three continents in north hemisphere over last two decades

Through synthesizing bulk precipitation chemistry in forest sites (n = 128) from three monitoring networks, (NADP in Northern America, EMEP in Europe, and EANET in East Asia), this study quantifies the temporal changes of precipitation acidity and its dominant acidifying agents over the last two decades. Results show distinct declines of sulfate and nitrate depositions and increases of precipitation pH in northeast America and central and east Europe, but not in Asia during 1999 and 2018. The decreases of sulfate and nitrate depositions likely reflect the long-term effort of pollutant emission controls. The temporal pattern of sulfate (SO42−)/nitrate (NO3−) and ammonium nitrogen (NH4-N)/nitrate nitrogen (NO3-N) equivalent ratios indicate that acid rain in the NADP and EMEP have transitioned from sulfate-dominated to nitrate-dominated, and the DIN deposition has shifted from nitrate-dominated to ammonium-dominated in recent years, owing to reductions of sulfur dioxides (SO2) and nitrogen oxides (NOx) emissions. In contrast, sulfate still plays a dominant role on the acidity of precipitation than nitrate in Asia, and NH4-N deposition also has a significant contribution in N flux due to increasing trends of ammonia emissions in Southeast Asia.

Oligosaccharide mapping analysis by HILIC-ESI-HCD-MS/MS for structural elucidation of fucoidan from sea cucumber Holothuria floridana

The elucidation of precise structure of fucoidan is essential for understanding their structure-function relationship and promoting the development of marine drugs. In this work, we firstly reported the oligosaccharide mapping of fucoidan from Holothuria floridana using a combination of hydrothermal depolymerization, hydrophilic interaction liquid chromatography (HILIC) coupled with electrospray mass spectrometry (ESI-FTMS) and high energy collision-induced dissociation (HCD-MS/MS) and 2D NMR analysis. With careful selection of fully deprotonated molecular ions of fucoidan oligosaccharides and their NaBD4 reduced alditols, HILIC-ESI-HCD-MS/MS provided structurally relevant glycosidic product ions with no sulfate loss for definitive assignment of sequence and sulfation pattern of all the oligosaccharides and their isomers from dp2 to dp7 from hydrothermal depolymerization. The oligosaccharide mapping clarified the structure of fucoidan with various oligosaccharide domains with 2,4-di-O-sulfated and 2-O sulfated fucose residues.

Structural and kinetic analyses of holothurian sulfated glycans suggest potential treatment for SARS-CoV-2 infection

Certain sulfated glycans, including those from marine sources, can show potential effects against SARS-CoV-2. Here, a new fucosylated chondroitin sulfate (FucCS) from the sea cucumber Pentacta pygmaea (PpFucCS) (MW ∼10–60 kDa) was isolated and structurally characterized by NMR. PpFucCS is composed of {→3)-β-GalNAcX-(1→4)-β-GlcA-[(3→1)Y]-(1→}, where X = 4S (80%), 6S (10%) or nonsulfated (10%), Y = α-Fuc2,4S (40%), α-Fuc2,4S-(1→4)-α-Fuc (30%), or α-Fuc4S (30%), and S = SO3−. The anti-SARS-CoV-2 activity of PpFucCS and those of the FucCS and sulfated fucan isolated from Isostichopus badionotus (IbFucCS and IbSF) were compared with that of heparin. IC50 values demonstrated the activity of the three holothurian sulfated glycans to be ∼12 times more efficient than heparin, with no cytotoxic effects. The dissociation constant (KD) values obtained by surface plasmon resonance of the wildtype SARS-CoV-2 spike (S)-protein receptor-binding domain (RBD) and N501Y mutant RBD in interactions with the heparin-immobilized sensor chip were 94 and 1.8 × 103 nM, respectively. Competitive surface plasmon resonance inhibition analysis of PpFucCS, IbFucCS, and IbSF against heparin binding to wildtype S-protein showed IC50 values (in the nanomolar range) 6, 25, and 6 times more efficient than heparin, respectively. Data from computational simulations suggest an influence of the sulfation patterns of the Fuc units on hydrogen bonding with GlcA and that conformational change of some of the oligosaccharide structures occurs upon S-protein RBD binding. Compared with heparin, negligible anticoagulant action was observed for IbSF. Our results suggest that IbSF may represent a promising molecule for future investigations against SARS-CoV-2.

Advanced Molecular Dynamics Approaches to Model a Tertiary Complex APRIL/TACI with Long Glycosaminoglycans.

Glycosaminoglycans (GAGs) are linear anionic periodic polysaccharides participating in a number of biologically relevant processes in the extracellular matrix via interactions with their protein targets. Due to their periodicity, conformational flexibility, pseudo-symmetry of the sulfation pattern, and the key role of electrostatics, these molecules are challenging for both experimental and theoretical approaches. In particular, conventional molecular docking applied for GAGs longer than 10-mer experiences severe difficulties. In this work, for the first time, 24- and 48-meric GAGs were docked using all-atomic repulsive-scaling Hamiltonian replica exchange molecular dynamics (RS-REMD), a novel methodology based on replicas with van der Waals radii of interacting molecules being scaled. This approach performed well for proteins complexed with oligomeric GAGs and is independent of their length, which distinguishes it from other molecular docking approaches. We built a model of long GAGs in complex with a proliferation-inducing ligand (APRIL) prebound to its receptors, the B cell maturation antigen and the transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI). Furthermore, the prediction power of the RS-REMD for this tertiary complex was evaluated. We conclude that the TACI–GAG interaction could be potentially amplified by TACI’s binding to APRIL. RS-REMD outperformed Autodock3, the docking program previously proven the best for short GAGs.

Decoding perineuronal net glycan sulfation patterns in the Alzheimer's disease brain.

The extracellular matrix (ECM) of the brain comprises unique glycan "sulfation codes" that influence neurological function. Perineuronal nets (PNNs) are chondroitin sulfate-glycosaminoglycan (CS-GAG) containing matrices that enmesh neural networks involved in memory and cognition, and loss of PNN matrices is reported in patients with neurocognitive and neuropsychiatric disorders including Alzheimer's disease (AD). Using liquid chromatography tandem mass spectrometry (LC-MS/MS), we show that patients with a clinical diagnosis of AD-related dementia undergo a re-coding of their PNN-associated CS-GAGs that correlates to Braak stage progression, hyperphosphorylated tau (p-tau) accumulation, and cognitive impairment. As these CS-GAG sulfation changes are detectable prior to the regional onset of classical AD pathology, they may contribute to the initiation and/or progression of the underlying degenerative processes and implicate the brain matrix sulfation code as a key player in the development of AD clinicopathology.

Exploring the sulfate patterns of chondroitin sulfate/dermatan sulfate and keratan sulfate in human pancreatic cancer

This study was designed to explore the sulfation patterns of chondroitin sulfate (CS)/dermatan sulfate (DS), and keratan sulfate (KS) and the expression of carbohydrate sulfotransferases (CHSTs) in 26 pancreatic tumor and normal tissues. CS/DS and KS profiles were simultaneously determined. Pancreatic tumor tissues exhibited increased ΔDi-0S, ΔDi-4S, and ΔDi-6S levels, with absolute ΔDi-4S content being highest, followed by ΔDi-6S. However, as for the contents of KS-6S and KS-6S,6'S, there were no significant regular change. The expression levels of CHST1 and CHST4 were 37 and 15 times higher than those in normal tissues. PCA and OPLS-DA revealed that ΔDi-4S and ΔDi-6S levels could be reliably used to differentiate between healthy and cancerous tissues. The up-regulation of CHST3, CHST12, CHST13, and CHST15 was directly correlated with C-4 and C-6 sulfation. These data provide a foundation for future studies of the role of ΔDi-4S and ΔDi-6S in the progression of pancreatic cancer.

Structural Determinants of Substrate Recognition and Catalysis by Heparan Sulfate Sulfotransferases.

Heparan sulfate (HS) and heparin contain imprinted "sulfation codes", which dictate their diverse physiological and pathological functions. A group of orchestrated biosynthetic enzymes cooperate in polymerizing and modifying HS chains. The biotechnological development of enzymes that can recreate this sulfation pattern on synthetic heparin is challenging, primarily due to the paucity of quantitative data for sulfotransferase enzymes. Herein, we identified critical structural characteristics that determine substrate specificity and shed light on the catalytic mechanism of sugar sulfation of two HS sulfotransferases, 2-O-sulfotransferase (HS2ST) and 6-O-sulfotransferase (HS6ST). Two sets of molecular clamps in HS2ST recognize appropriate substrates; these clamps flank the acceptor binding site on opposite sides. The hexuronic epimers, and not their puckers, have a critical influence on HS2ST selectivity. In contrast, HS6ST recognizes a broader range of substrates. This promiscuity is granted by a conserved tryptophan residue, W210, that positions the acceptor within the active site for catalysis by means of strong electrostatic interactions. Lysines K131 and K132 act in concert with a second tryptophan, W153, shedding water molecules from within the active site, thus providing HS6ST with a binding preference toward 2-O-sulfated substrates. QM/MM calculations provided valuable mechanistic insights into the catalytic process, identifying that the sulfation of both HS2ST and HS6ST follows a SN2-like mechanism. When they are taken together, our findings reveal the molecular basis of how these enzymes recognize different substrates and catalyze sugar sulfation, enabling the generation of enzymes that could create specific heparin epitopes.

Selective Binding of Heparin/Heparan Sulfate Oligosaccharides to Factor H and Factor H-Related Proteins: Therapeutic Potential for C3 Glomerulopathies.

Complement dysregulation is characteristic of the renal diseases atypical hemolytic uremic syndrome (aHUS) and complement component 3 glomerulopathy (C3G). Complement regulatory protein Factor H (FH) inhibits complement activity, whereas FH-related proteins (FHRs) lack a complement regulatory domain. FH and FHRs compete for binding to host cell glycans, in particular heparan sulfates (HS). HS is a glycosaminoglycan with an immense structural variability, where distinct sulfation patterns mediate specific binding of proteins. Mutations in FH, FHRs, or an altered glomerular HS structure may disturb the FH : FHRs balance on glomerular endothelial cells, thereby leading to complement activation and the subsequent development of aHUS/C3G. In this study, we aimed to identify specific HS structures that could specifically compete off FHRs from HS glycocalyx (HSGlx), without interfering with FH binding. FH/FHR binding to human conditionally immortalized glomerular endothelial cells (ciGEnCs) and HSGlx purified from ciGEnC glycocalyx was assessed. HS modifications important for FH/FHR binding to HSGlx were analyzed using selectively desulfated heparins in competition with purified HSGlx. We further assessed effects of heparinoids on FHR1- and FHR5-mediated C3b deposition on ciGEnCs. In the presence of C3b, binding of FH, FHR1 and FHR5 to ciGEnCs was significantly increased, whereas binding of FHR2 was minimal. FHR1 and 5 competitively inhibited FH binding to HSGlx, leading to alternative pathway dysregulation. FHR1 and FHR5 binding was primarily mediated by N-sulfation while FH binding depended on N-, 2-O- and 6-O-sulfation. Addition of 2-O-desulfated heparin significantly reduced FHR1- and FHR5-mediated C3b deposition on ciGEnCs. We identify 2-O-desulfated heparin derivatives as potential therapeutics for C3G and other diseases with dysregulated complement.

Impact of growth medium salinity on galactoxylan exopolysaccharides of Porphyridium purpureum

Porphyridium purpureum is a red saline microalga rich in protein and floridean starch with the ability to excrete high amounts of sulfated polysaccharides (sEPS) into the growth medium. This microalga has been used for feeding fish in aquaculture. P. purpureum is easily cultivated and could change its growth rate and composition in response to environmental variations. Thus, the effect of growth medium salinity (18, 32, and 50 g/L NaCl) on P. purpureum cell growth, biomass composition, and extracellular polysaccharides production yield and chemical structure were evaluated. A maximum growth of an estimated 5.7 × 106 cells/mL achieved at a salinity of 32 g/L NaCl, after 19 days of growth. Different from the almost unchanged biomass composition of algal cells, the yield and structure of sEPS were affected by the salinity of the growth media. The salinity of the growth media led to a slight change of the sulfation pattern of the glucuronoglucogalactoxylan, as the sEPS produced by P. purpureum growing at lower salinity tended to be more sulfated in the O-3 position of xylose and the O-6 position of glucose, whereas the sEPS at higher salinity tended to be more sulfated in the O-4 position of xylose and glucose. The sEPS produced at higher salinity also revealed higher linear 2-Gal, 3-Gal, and 4-Gal residues. In all samples, the most representative sugars residues were constituted by t-Xyl, t-Xyl-4S, 3-Xyl, 4-Xyl, t-Glc, 3-Glc-6S, t-Gal, and 2,3,4-Gal.The sEPS showed immunostimulatory effect on B lymphocytes in vitro and could be produced at large scale at an outdoor 800 L-flat panel photobioreactor with higher yield. These results pave the way for the potential use of P. purpureum sEPS to enhance humoral immune activity of fish in aquaculture.

Chondroitin 6-sulfate-binding peptides improve recovery in spinal cord-injured mice

The role of glycosaminoglycan sulfation patterns, particularly in regard to scar formation and inhibition of neuritogenesis, has been mainly studied in cell culture with a focus on chondroitin 4-sulfate. In this study, we investigated chondroitin 6-sulfate (C6S) and found that it also inhibits neurite outgrowth of mouse cerebellar granule neurons in vitro. To examine whether the inhibitory activity of C6S could be neutralized, seven previously characterized high-affinity C6S-binding peptides were tested, among which three peptides neutralized the inhibitory functions of C6S. We further investigated these peptides in a mouse model of spinal cord injury, since upregulation of C6S expression in the glial scar following injury has been associated with reduced axonal regrowth and functional recovery. We here subjected mice to severe compression injury at thoracic levels T7-T9, immediately followed by inserting gelfoam patches soaked in C6S-binding peptides or in a control peptide. Application of C6S-binding peptides led to functional recovery after injury and prevented fibrotic glial scar formation, as seen by decreased activation of astrocytes and microglia/macrophages. Decreased expression of several lecticans and deposition of fibronectin at the site of injury were also observed. Application of C6S-binding peptides led to axonal regrowth and inhibited the C6S-mediated activation of RhoA/ROCK and decrease of PI3K–Akt–mTOR signaling pathways. Taken together, these results indicate that treatment with C6S-binding peptides improves functional recovery in a mouse model of spinal cord injury.

Single-molecule force spectroscopy reveals structural differences of heparan sulfate chains during binding to vitronectin.

The syndecans represent an ongoing research field focused on their regulatory roles in normal and pathological conditions. The role of syndecans in cancer progression is well documented, implicating their importance in diagnosis and even proposing various potential cancer treatments. Thus, the characterization of the unbinding properties at the single-molecule level will appeal to their use as targets for therapeutics. In our study, syndecan-1 and syndecan-4 were measured during the interaction with the vitronectin HEP II binding site. Our findings show that syndecans are calcium ion dependent molecules that reveal distinct, unbinding properties indicating the alterations in the structure of heparan sulfate (HS) chains, possibly in the chain sequence or sulfation pattern. In this way, we suppose that HS chain affinity to extracellular matrix proteins may govern cancer invasion by altering the syndecans' ability to interact with cancer-related receptors present in the tumor microenvironment, thereby promoting the activation of various signaling cascades regulating tumor cell behavior.

Chondroitin Sulfate/Dermatan Sulfate-Protein Interactions and Their Biological Functions in Human Diseases: Implications and Analytical Tools.

Chondroitin sulfate (CS) and dermatan sulfate (DS) are linear anionic polysaccharides that are widely present on the cell surface and in the cell matrix and connective tissue. CS and DS chains are usually attached to core proteins and are present in the form of proteoglycans (PGs). They not only are important structural substances but also bind to a variety of cytokines, growth factors, cell surface receptors, adhesion molecules, enzymes and fibrillary glycoproteins to execute series of important biological functions. CS and DS exhibit variable sulfation patterns and different sequence arrangements, and their molecular weights also vary within a large range, increasing the structural complexity and diversity of CS/DS. The structure-function relationship of CS/DS PGs directly and indirectly involves them in a variety of physiological and pathological processes. Accumulating evidence suggests that CS/DS serves as an important cofactor for many cell behaviors. Understanding the molecular basis of these interactions helps to elucidate the occurrence and development of various diseases and the development of new therapeutic approaches. The present article reviews the physiological and pathological processes in which CS and DS participate through their interactions with different proteins. Moreover, classic and emerging glycosaminoglycan (GAG)-protein interaction analysis tools and their applications in CS/DS-protein characterization are also discussed.

The degree of polymerization and sulfation patterns in heparan sulfate are critical determinants of cytomegalovirus entry into host cells.

Several enveloped viruses, including herpesviruses attach to host cells by initially interacting with cell surface heparan sulfate (HS) proteoglycans followed by specific coreceptor engagement which culminates in virus-host membrane fusion and virus entry. Interfering with HS-herpesvirus interactions has long been known to result in significant reduction in virus infectivity indicating that HS play important roles in initiating virus entry. In this study, we provide a series of evidence to prove that specific sulfations as well as the degree of polymerization (dp) of HS govern human cytomegalovirus (CMV) binding and infection. First, purified CMV extracellular virions preferentially bind to sulfated longer chain HS on a glycoarray compared to a variety of unsulfated glycosaminoglycans including unsulfated shorter chain HS. Second, the fraction of glycosaminoglycans (GAG) displaying higher dp and sulfation has a larger impact on CMV titers compared to other fractions. Third, cell lines deficient in specific glucosaminyl sulfotransferases produce significantly reduced CMV titers compared to wild-type cells and virus entry is compromised in these mutant cells. Finally, purified glycoprotein B shows strong binding to heparin, and desulfated heparin analogs compete poorly with heparin for gB binding. Taken together, these results highlight the significance of HS chain length and sulfation patterns in CMV attachment and infectivity.

The potential role of glycosaminoglycans in serum amyloid A fibril formation by in silico approaches

Serum amyloid A (SAA) is actively involved in such pathological processes as atherosclerosis, rheumatoid arthritis, cancer and Alzheimer's disease by its aggregation. One of the factors that can attenuate its aggregation and so affects its physiological role is its interactions with glycosminoglycans (GAGs), linear anionic periodic polysaccharides. These molecules located in the extracellular matrix of the cell are highly variable in their chemical composition and sulfation patterns. Despite the available experimental evidence of SAA-GAG interactions, no mechanistic details at atomic level have been reported for these systems so far. In our work we aimed to apply diverse computational tools to characterize SAA-GAG complexes formation and to answer questions about their potential specificity, energetic patterns, particular SAA residues involved in these interactions, favourable oligomeric state of the protein and the potential influence of GAGs on SAA aggregation. Molecular docking, conventional and replica exchange molecular dynamics approaches were applied to corroborate the experimental knowledge and to propose the corresponding molecular models. SAA-GAG complex formation was found to be electrostatics-driven and rather unspecific of a GAG sulfation pattern, more favorable for the dimer than for the monomer when binding to a short GAG oligosaccharide through its N-terminal helix, potentially contributing to the unfolding of this helix, which could lead to the promotion of the protein aggregation. The data obtained add to the specific knowledge on SAA-GAG systems and deepen the general understanding of protein-GAG interactions that is of a considerable value for the development of GAG-based approaches in a broad theurapeutic context.

Structural insights into the modulation of PDGF/PDGFR-β complexation by hyaluronan derivatives.

Angiogenesis is an important physiological process playing a crucial role in wound healing and cancer progression. Vascular endothelial growth factor (VEGF) and platelet derived growth factor (PDGF) are key players in angiogenesis. Based on previous findings regarding the modulation of VEGF activity by glycosaminoglycans (GAG), here we explore the interaction of hyaluronan (HA)-based GAG with PDGF and its receptor PDGFR-β by applying molecular modeling and dynamics simulations in combination with surface plasmon resonance (SPR). Computational analysis on the interaction of oligo-hyaluronan derivatives with different sulfation pattern and functionalization shows that these GAG interact with PDGF in relevant regions for receptor recognition, and that high sulfation as well as modification with the TAMRA group convey stronger binding. On the other hand, the studied oligo-hyaluronan derivatives are predicted to scarcely recognize PDGFR-β. SPR results are in line with the computational predictions regarding the binding pattern of HA tetrasaccharide (HA4) derivatives to PDGF and PDGFR-β. Furthermore, our experimental results also show that the complexation of PDGF to PDGFR-β can be modulated by HA4 derivatives. The results found open the path for considering HA4 derivatives as potential candidates to be exploited for modulation of the PDGF/PDGFR-β signaling system in angiogenesis and related disease conditions.