Chondroitin sulfate/dermatan sulfate sulfatases from mammals and bacteria

A role for decorin in improving motor deficits after traumatic brain injury

Traumatic brain injury (TBI) is the leading cause of death and disability due to injury worldwide. Extracellular matrix (ECM) remodeling is known to significantly contribute to TBI pathophysiology. Glycosaminoglycans, which are long-chain, variably sulfated polysaccharides abundant within the ECM, have previously been shown to be substantially altered after TBI. In this study, we sought to delineate the dynamics of glycosaminoglycan alterations after TBI and discover the precise biologic processes responsible for observed glycosaminoglycan changes after injury. We performed state-of-the art mass spectrometry on brain tissues isolated from mice after TBI or craniotomy-alone. We observed dynamic changes in glycosaminoglycans at Day 1 and 7 post-TBI, with heparan sulfate, chondroitin sulfate, and hyaluronan remaining significantly increased after a week vis-à-vis craniotomy-alone tissues. We did not observe appreciable changes in circulating glycosaminoglycans in mice after experimental TBI compared to craniotomy-alone nor in patients with TBI and severe polytrauma compared to control patients with mild injuries, suggesting increases in injury site glycosaminoglycans are driven by local synthesis. We subsequently performed an unbiased whole genome transcriptomics analysis on mouse brain tissues 7 days post-TBI and discovered a significant induction of hyaluronan synthase 2, glypican-3, and decorin. The functional role of decorin after injury was further examined through multimodal behavioral testing comparing wild-type and Dcn-/- mice. We discovered that genetic ablation of Dcn led to an overall negative effect of TBI on function, exacerbating motor impairments after TBI. Collectively, our results provide a spatiotemporal characterization of post-TBI glycosaminoglycan alterations in the brain ECM and support an important adaptive role for decorin upregulation after TBI.

A novel 4-O-endosulfatase with high potential for the structure-function studies of chondroitin sulfate/dermatan sulfate

The sulfation patterns of chondroitin sulfate (CS)/dermatan sulfate (DS), which encode unique biological information, play critical roles in the various biological functions of CS/DS chains. CS/DS sulfatases, which can specifically hydrolyze sulfate groups, could potentially be essential tools for deciphering and changing the biological information encoded by these sulfation patterns. However, endosulfatase with high activity to efficiently hydrolyze the sulfate groups inside CS/DS polysaccharides have rarely been identified, which hinders the practical applications of CS/DS sulfatases. Herein, a novel CS/DS 4-O-endosulfatase (endoBI4SF) with a strong ability to completely remove 4-O-sulfated groups inside various CS/DS polysaccharides was identified and successfully used to investigate the biological roles of 4-O-sulfated CS/DS in vitro and in vivo. This study provides a much-needed tool to tailor the sulfation patterns and explore the related functions of 4-O-sulfated CS/DS chains in vitro and in vivo.

Clostridioides difficile infection: traversing host-pathogen interactions in the gut

C. difficile is the primary cause for nosocomial infective diarrhoea. For a successful infection, C. difficile must navigate between resident gut bacteria and the harsh host environment. The perturbation of the intestinal microbiota by broad-spectrum antibiotics alters the composition and the geography of the gut microbiota, deterring colonization resistance, and enabling C. difficile to colonize. This review will discuss how C. difficile interacts with and exploits the microbiota and the host epithelium to infect and persist. We provide an overview of C. difficile virulence factors and their interactions with the gut to aid adhesion, cause epithelial damage and mediate persistence. Finally, we document the host responses to C. difficile, describing the immune cells and host pathways that are associated and triggered during C. difficile infection.

Effects of Dermatan Sulfate from Marine Invertebrate Styela plicata in the Wound Healing Pathway: A Natural Resource Applied to Regenerative Therapy

Acute and chronic dermatological injuries need rapid tissue repair due to the susceptibility to infections. To effectively promote cutaneous wound recovery, it is essential to develop safe, low-cost, and affordable regenerative tools. Therefore, we aimed to identify the biological mechanisms involved in the wound healing properties of the glycosaminoglycan dermatan sulfate (DS), obtained from ascidian Styela plicata, a marine invertebrate, which in preliminary work from our group showed no toxicity and promoted a remarkable fibroblast proliferation and migration. In this study, 2,4-DS (50 µg/mL)-treated and control groups had the relative gene expression of 84 genes participating in the healing pathway evaluated. The results showed that 57% of the genes were overexpressed during treatment, 16% were underexpressed, and 9.52% were not detected. In silico analysis of metabolic interactions exhibited overexpression of genes related to: extracellular matrix organization, hemostasis, secretion of inflammatory mediators, and regulation of insulin-like growth factor transport and uptake. Furthermore, in C57BL/6 mice subjected to experimental wounds treated with 0.25% 2,4-DS, the histological parameters demonstrated a great capacity for vascular recovery. Additionally, this study confirmed that DS is a potent inducer of wound-healing cellular pathways and a promoter of neovascularization, being a natural ally in the tissue regeneration strategy.

Spatiotemporal diversity and regulation of glycosaminoglycans in cell homeostasis and human disease

Glycosaminoglycans (GAGs) are long, linear polysaccharides that are ubiquitously expressed on the cell surface and in the extracellular matrix of all animal cells. These complex carbohydrates play important roles in many cellular processes and have been implicated in many disease states, including cancer, inflammation, and genetic disorders. GAGs are among the most complex molecules in biology with enormous information content and extensive structural and functional heterogeneity. GAG biosynthesis is a nontemplate-driven process facilitated by a large group of biosynthetic enzymes that have been extensively characterized over the past few decades. Interestingly, the expression of the enzymes and the consequent structure and function of the polysaccharide chains can vary temporally and spatially during development and under certain pathophysiological conditions, suggesting their assembly is tightly regulated in cells. Due to their many key roles in cell homeostasis and disease, there is much interest in targeting the assembly and function of GAGs as a therapeutic approach. Recent advances in genomics and GAG analytical techniques have pushed the field and generated new perspectives on the regulation of mammalian glycosylation. This review highlights the spatiotemporal diversity of GAGs and the mechanisms guiding their assembly and function in human biology and disease.

CD44-Targeted Nanocarrier for Cancer Therapy

Cluster of differentiation 44 (CD44) is a cell surface glycoprotein overexpressed in varieties of solid tumors including pancreatic, breast, ovary, brain, and lung cancers. It is a multi-structural glycoprotein of the cell surface which is majorly involved in cell proliferation, cell-to-cell interaction, cellular migration, inflammation, and generation of immune responses. Numerous studies focus on the development of nanocarriers for active targeting of the CD44 receptor to improve efficacy of targeting chemotherapy and achieve precise chemotherapy by defining the release, uptake, and accumulation of therapeutic agents. The CD44 receptor has a selective binding affinity towards hyaluronic and chondroitin sulfate (CS). Taking this into consideration, this review focused on the role of CD44 in cancer and its therapy using several nanocarriers such as polymeric/non-polymeric nanoparticles, dendrimer, micelles, carbon nanotubes, nanogels, nanoemulsions etc., for targeted delivery of several chemotherapeutic molecules and nucleic acid. This review also illuminates the role of hyaluronic acid (HA) in cancer therapy, interaction of HA with CD44, and various approaches to target CD44-overexpressed neoplastic cells.

Ecological and evolutionary diversification of sulphated polysaccharides in diverse photosynthetic lineages: A review

Sulphated polysaccharides (SPs) are carbohydrate macromolecules with sulphate esters that are found among marine algae, seagrasses, mangroves and some terrestrial plants. The sulphate concentration in the ocean (28 mM) since ancient time could have driven the production of SPs in marine algae. SPs have a gelatinous property that can protect marine algae against desiccation and salinity stress. Agar and carrageenan are red algal SPs that are widely used as gelling agents in the food and pharmaceutical industries. The information on the SPs from freshwater and land plants are limited. In this review, we reviewed the taxonomic distribution and composition of SPs in different photosynthetic lineages, and explored the association of SP production in these diversified photosynthetic organisms with evolution history and environmental stresses. We also reviewed the genes/proteins involved in SP biosynthesis. Insights into SP biosynthetic machinery may shed light on the evolution that accompanied adaptation to life on earth.

Identification and Action Patterns of Two Chondroitin Sulfate Sulfatases From a Marine Bacterium Photobacterium sp. QA16

Chondroitin sulfate (CS)/dermatan sulfate (DS) is a kind of sulfated polyanionic, linear polysaccharide belonging to glycosaminoglycan. CS/DS sulfatases, which specifically hydrolyze sulfate groups from CS/DS oligo-/polysaccharides, are potential tools for structural and functional studies of CD/DS. However, only a few sulfatases have been reported and characterized in detail to date. In this study, two CS/DS sulfatases, PB_3262 and PB_3285, were identified from the marine bacterium Photobacterium sp. QA16 and their action patterns were studied in detail. PB_3262 was characterized as a novel 4-O-endosulfatase that can effectively and specifically hydrolyze the 4-O-sulfate group of disaccharide GlcUAβ1–3GalNAc(4-O-sulfate) but not GlcUAβ1–3GalNAc(4,6-O-sulfate) and IdoUAα1–3GalNAc(4-O-sulfate) in CS/DS oligo-/polysaccharides, which is very different from the identified 4-O-endosulfatases in the substrate profile. In contrast, PB_3285 specifically hydrolyzes the 6-O-sulfate groups of GalNAc(6-O-sulfate) residues located at the reducing ends of the CS chains and is the first recombinantly expressed 6-O-exosulfatase to effectively act on CS oligosaccharides.

Extracellular Matrix Deposition and Remodeling after Corneal Alkali Burn in Mice

Corneal transparency relies on the precise arrangement and orientation of collagen fibrils, made of mostly Type I and V collagen fibrils and proteoglycans (PGs). PGs are essential for correct collagen fibrillogenesis and maintaining corneal homeostasis. We investigated the spatial and temporal distribution of glycosaminoglycans (GAGs) and PGs after a chemical injury. The chemical composition of chondroitin sulfate (CS)/dermatan sulfate (DS) and heparan sulfate (HS) were characterized in mouse corneas 5 and 14 days after alkali burn (AB), and compared to uninjured corneas. The expression profile and corneal distribution of CS/DSPGs and keratan sulfate (KS) PGs were also analyzed. We found a significant overall increase in CS after AB, with an increase in sulfated forms of CS and a decrease in lesser sulfated forms of CS. Expression of the CSPGs biglycan and versican was increased after AB, while decorin expression was decreased. We also found an increase in KS expression 14 days after AB, with an increase in lumican and mimecan expression, and a decrease in keratocan expression. No significant changes in HS composition were noted after AB. Taken together, our study reveals significant changes in the composition of the extracellular matrix following a corneal chemical injury.

Investigation of action pattern of a novel chondroitin sulfate/dermatan sulfate 4-O-endosulfatase

Recently, a novel CS/DS 4-O-endosulfatase was identified from a marine bacterium and its catalytic mechanism was investigated further (Wang, W., et. al (2015) J. Biol. Chem.290, 7823-7832; Wang, S., et. al (2019) Front. Microbiol.10, 1309). In the study herein, we provide new insight about the structural characteristics of the substrate which determine the activity of this enzyme. The substrate specificities of the 4-O-endosulfatase were probed by using libraries of structure-defined CS/DS oligosaccharides issued from synthetic and enzymatic sources. We found that this 4-O-endosulfatase effectively remove the 4-O-sulfate of disaccharide sequences GlcUAβ1-3GalNAc(4S) or GlcUAβ1-3GalNAc(4S,6S) in all tested hexasaccharides. The sulfated GalNac residue is resistant to the enzyme when adjacent uronic residues are sulfated as shown by the lack of enzymatic desulfation of GlcUAβ1-3GalNAc(4S) connected to a disaccharide GlcUA(2S)β1-3GalNAc(6S) in an octasaccharide. The 3-O-sulfation of GlcUA was also shown to hinder the action of this enzyme. The 4-O-endosulfatase exhibited an oriented action from the reducing to the non-reducing whatever the saturation or not of the non-reducing end. Finally, the activity of the 4-O-endosulfatase decreases with the increase in substrate size. With the deeper understanding of this novel 4-O-endosulfatase, such chondroitin sulfate (CS)/dermatan sulfate (DS) sulfatase is a useful tool for exploring the structure-function relationship of CS/DS.

Cloning and characterization of a novel chondroitinase ABC categorized into a new subfamily of polysaccharide lyase family 8

Chondroitinases degrade chondroitin sulfate (CS) into oligosaccharides, of which the biological activities have vital roles in various fields. Some chondroitinases in polysaccharide lyase family 8 (PL8) have been classified into four subfamilies (PL8_1, PL8_2, PL8_3, and PL8_4) based on their sequence similarity and substrate specificities. In this study, a gene, vpa_0049, was cloned from marine bacterium Vibrio sp. QY108. The encoded protein, Vpa_0049, did not belong to the four existing subfamilies in PL8 based on phylogenetic analysis. Vpa_0049 could degrade various glycosaminoglycans (CS-A, CS-B, CS-C, CS-D, and HA) into unsaturated disaccharides in an endolytic manner, which was different from PL8 lyases of four existing subfamilies. The maximum activity of Vpa_0049 on different glycosaminoglycan substrates appeared at 30-37 °C and pH 7.0-8.0 in the presence of NaCl. Vpa_0049 showed approximately 50% of maximum activity towards CS-B and HA at 0 °C. It was stable in alkaline conditions (pH 8.0-10.6) and 0-30 °C. Our study provides a new broad-substrate chondroitinase and presents an in-depth understanding of PL8.

Comparative Study of Two Chondroitin Sulfate/Dermatan Sulfate 4-O-Sulfatases With High Identity

Chondroitin sulfate/dermatan sulfate (CS/DS) sulfatases are potential tools for structural and functional studies of CD/DS chains. In our previous study, a CS/DS 4-O-endosulfatase (endoVB4SF) was identified from a marine bacterium (Wang et al., 2015). Herein, another CS/DS 4-O-sulfatase (exoPB4SF) was identified from a Photobacterium sp. ExoPB4SF shares an 83% identity with endoVB4SF but showed strict exolytic activity. Comparative studies were performed for both enzymes on the basis of biochemical features, substrate-degrading patterns and three-dimensional structures. exoPB4SF exhibited a wider temperature and pH adaptability and better thermostability than endoVB4SF. Furthermore, exoPB4SF is a strict exolytic sulfatase that only releases the sulfate group from the GalNAc residue located at the reducing end, whereas endoVB4SF preferentially removed sulfate esters from the reducing end toward the non-reducing end though its directional degradation property was not strict. In addition, the structure of endoVB4SF was determined by X-ray crystallography at 1.95 Å. It adopts a globular conformation with two monomers per asymmetric unit. The exoPB4SF structure was constructed by homology modeling. Molecular docking results showed that although the residues around the catalytic center are conserved, the residues at the active site of endoVB4SF adopted a more favorable conformation for the binding of long CS/DS chains than those of exoPB4SF, which may explain why the two highly homogenous sulfatases possessed different action patterns. The results of this study provide insight into the structure-function relationship of CS/DS endo- and exosulfatases for the first time.

Identification and Signature Sequences of Bacterial Δ4,5Hexuronate-2-O-Sulfatases

Glycosaminoglycan (GAG) sulfatases, which catalyze the hydrolysis of sulfate esters from GAGs, belong to a large and conserved sulfatase family. Bacterial GAG sulfatases are essential in the process of sulfur cycling and are useful for the structural analysis of GAGs. Only a few GAG-specific sulfatases have been studied in detail and reported to date. Herein, the GAG-degrading Photobacterium sp. FC615 was isolated from marine sediment, and a novel Δ^4,5hexuronate-2-O-sulfatase (PB2SF) was identified from this bacterium. PB2SF specifically removed 2-O-sulfate from the unsaturated hexuronate residue located at the non-reducing end of GAG oligosaccharides produced by GAG lyases. A structural model of PB2SF was constructed through a homology-modeling method. Six conserved amino acids around the active site were chosen for further analysis using site-directed mutagenesis. N113A, K141A, K141H, H143A, H143K, H205A, and H205K mutants exhibited only feeble activity, while the H310A, H310K, and D52A mutants were totally inactive, indicating that these conserved residues, particularly Asp52 and His310, were essential in the catalytic mechanism. Furthermore, bioinformatic analysis revealed that GAG sulfatases with specific degradative properties clustered together in the neighbor-joining phylogenetic tree. Based on this finding, 60 Δ^4,5hexuronate-2-O-sulfatases were predicted in the NCBI protein database, and one with relatively low identity to PB2SF was characterized to confirm our prediction. Moreover, the signature sequences of bacterial Δ^4,5hexuronate-2-O-sulfatases were identified. With the reported signature motifs, the sulfatase sequence of the Δ^4,5hexuronate-2-O-sulfatase family could be simply identified before cloning. Taken together, the results of this study should aid in the identification and further application of novel GAG sulfatases.

Oral Bioavailability and Pharmacokinetics of Nonanimal Chondroitin Sulfate and Its Constituents in Healthy Male Volunteers

The pharmacokinetic profile of a new 800-mg tablet of nonanimal chondroitin sulfate (CS) (Mythocondro®, 800-mg tablets, Gnosis S.p.A., Italy) was investigated vs an animal CS in healthy volunteers for a total period of 48 hours. After a single 2400-mg dose of the test and the reference formulation, total CS, the compositional disaccharides (ΔDi6S, ΔDi4S and ΔDi0S), and the overall charge density were quantified in plasma. The safety and tolerability profile after a single dose of this new nonanimal CS tablets was excellent. After baseline-corrected concentrations, an overall greater plasma concentration was observed after 24 hours of ∼44% and after 48 hours of ∼45% from administration of nonanimal when compared to animal-derived CS. Moreover, nonanimal CS increases the specific sulfation in the 6-position of N-acetyl-galactosamine in human plasma CS and, as a consequence, the overall charge density, reaching double values (0.91), after 48 hours compared to bovine CS and to endogenous CS. In conclusion, nonanimal CS, possessing a lower molecular weight than an animal-derived sample, produces a greater CS concentration for a more prolonged period of time in plasma and an increase in charge density and specific 6-sulfation of endogenous plasma CS.