N-acetyl-D-glucosamine-coated polyamidoamine dendrimer promotes tumor-specific B cell responses via natural killer cell activation

Construction of Chitinase Complexes Using Self-Assembly Systems for Efficient Hydrolysis of Chitin

Chitin biomass is the second most abundant natural polysaccharide after cellulose on the earth, yet its recalcitrance to degrade and utilize severely limits its application. However, many microorganisms, such as Serratia marcescen, can secrete a range of free chitinases to degrade chitin, though their activity is typically insufficient to meet industrial demands. In this study, we employed self-assembly systems, named SpyTag/SpyCatcher and SnoopTag/SnoopCatcher, to modularize the molecular design of CHB, ChiB, ChiC, and CBP21 derived from S. marcescens ATCC14756, and we successfully constructed a variety of chitinase complexes. The assembled complexes showed higher chitinolytic activity and stability, compared to free chitinase mixture. Moreover, the distinct arrangements and combinations of chitinases within these complexes led to varied activities, suggesting that the spatial proximity and substrate channeling effects contribute to the synergy of chitinase complexes. The findings lay a solid technical foundation for the application of chitinosome in the industrial production of N-acetylglucosamine and chitooligosaccharides.

Cyanovirin-N Binding to N-Acetyl-d-glucosamine Requires Carbohydrate-Binding Sites on Two Different Protomers

Cyanovirin-N (CV-N) binds high-mannose oligosaccharides on enveloped viruses with two carbohydrate-binding sites, one bearing high affinity and one low affinity to Manα(1-2)Man moieties. A tandem repeat of two CV-N molecules (CVN2) was tested for antiviral activity against human immunodeficiency virus type I (HIV-1) by using a domain-swapped dimer. CV-N was shown to bind N-acetylmannosamine (ManNAc) and N-acetyl-d-glucosamine (GlcNAc) when the carbohydrate-binding sites in CV-N were free to interact with these monosaccharides independently. CVN2 recognized ManNAc at a Kd of 1.4 μM and bound this sugar in solution, regardless of the lectin making amino acid side chain contacts on the targeted viral glycoproteins. An interdomain cross-contacting residue Glu41, which has been shown to be hydrogen bonding with dimannose, was substituted in the monomeric CV-N. The amide derivative of glucose, GlcNAc, achieved similar high affinity to the new variant CVN-E41T as high-mannose N-glycans, but binding to CVN2 in the nanomolar range with four binding sites involved or binding to the monomeric CVN-E41A. A stable dimer was engineered and expressed from the alanine-to-threonine-substituted monomer to confirm binding to GlcNAc. In summary, low-affinity binding was achieved by CVN2 to dimannosylated peptide or GlcNAc with two carbohydrate-binding sites of differing affinities, mimicking biological interactions with the respective N-linked glycans of interest and cross-linking of carbohydrates on human T cells for lymphocyte activation.

Determination and Correlation of Solubility of N-Acetylglucosamine in Four Aqueous Binary Solvents from 283.15 to 323.15 K

N-Acetylglucosamine (NAG) is a significant novel functional monosaccharide with a wide range of potential applications, such as in the medical and cosmetic fields. A gravimetric technique was used to assess the solubility of NAG in water, methanol, N,N-dimethylformamide, water + methanol, water + n-propanol, water + N,N-dimethylformamide, and water + acetonitrile at temperatures ranging from 283.15 to 323.15 K. The outcomes of the experiment demonstrated that the temperature and water content were positively correlated with the solubility of NAG in four experimental binary solvents. The order of solubility in the four aqueous solvent mixtures is water + DMF > water + methanol > water + n-propanol > water + acetonitrile. The solubility data was well correlated using the modified Apelblat model, the CNIBS/R-K model, and the Apelblat-Jouyban-Acree model. Experimental data from NAG will help guide the design of cooling and dissolution in crystallization processes.

Improving enzyme activity of glucosamine-6-phosphate synthase by semi-rational design strategy and computer analysis

OBJECTIVE

To improve enzyme activity of Glucosamine-6-phosphate synthase (Glms) of Bacillus subtilis by site saturation mutagenesis at Leu₅₉₃, Ala₅₉₄, Lys₅₉₅, Ser₅₉₆ and Val₅₉₇ based on computer-aided semi-rational design.

RESULTS

The results indicated that L₅₉₃S had the greatest effect on the activity of BsGlms and the enzyme activity increased from 5 to 48 U/mL. The mutation of L₅₉₃S increased the yield of glucosamine by 1.6 times that of the original strain. The binding energy of the mutant with substrate was reduced from - 743.864 to - 768.246 kcal/mol. Molecular dynamics simulation results showed that Ser₅₉₃ enhanced the flexibility of the protein, which ultimately led to increased enzyme activity.

CONCLUSION

We successfully improved BsGlms activity through computer simulation and site saturation mutagenesis. This combination of methodologies may fit into an efficient workflow for improving Glms and other proteins activity.

Enhancement of Production of D-Glucosamine in Escherichia coli by Blocking Three Pathways Involved in the Consumption of GlcN and GlcNAc

D-Glucosamine is a commonly used dietary supplement that promotes cartilage health in humans. Metabolic flux analysis showed that D-glucosamine production could be increased by blocking three pathways involved in the consumption of glucosamine-6-phosphate and acetylglucosamine-6-phosphate. By homologous single-exchange, two key genes (nanE and murQ) of Escherichia coli BL21 were knocked out, respectively. The D-glucosamine yields of the engineered strains E. coli BL21ΔmurQ and E. coli BL21ΔnanE represented increases by factors of 2.14 and 1.79, respectively. Meanwhile, for bifunctional gene glmU, we only knocked out its glucosamine-1-phosphate acetyltransferase domain by 3D structural analysis to keep the engineered strain E. coli BL21glmU-Δgpa survival, which resulted in an increase in the production of D-glucosamine by a factor of 2.16. Moreover, for further increasing D-glucosamine production, two genes encoding rate-limiting enzymes, named glmS and gna1, were coexpressed by an RBS sequence in those engineered strains. The total concentrations of D-glucosamine in E. coli BL21 glmU-Δgpa', E. coli BL21ΔmurQ', and E. coli BL21ΔnanE' were 2.65 g/L, 1.73 g/L, and 1.38 g/L, which represented increases by factors of 8.83, 5.76, and 3.3, respectively.

The role of natural killer cells in hepatocellular carcinoma development and treatment: A narrative review

A major obstacle for treatment of HCC is the inadequate efficacy and limitation of the available therapeutic options. Despite the recent advances in developing novel treatment options, HCC still remains one of the major causes of cancer morbidity and mortality around the world. Achieving effective treatment and eradication of HCC is a challenging task, however recent studies have shown that targeting Natural Killer cells, as major regulators of immune system, can help with the complete treatment of HCC, restoration of normal liver function and subsequently higher survival rate of HCC patients. Studies have shown that decrease in the frequency of NK cells, their dysfunction due to several factors such as dysregulation of receptors and their ligands, and imbalance of different types of inhibitory and stimulating microRNA expression is associated with higher rate of HCC progression and development, and poor survival outcome. Here in our review, we mainly focused on the importance of NK cells in HCC development and treatment.

In Vivo Anticancer Efficacy and Toxicity Studies of a Novel Polymer Conjugate N-Acetyl Glucosamine (NAG)-PEG-Doxorubicin for Targeted Cancer Therapy

A novel polymer-drug conjugate, polyethylene glycol-N-(acetyl)-glucosamine-doxorubicin (PEG-NAG-DOX) was evaluated in this study for its in vivo potential for treatment of tumours demonstrating improved efficacy and reduced toxicity. The proposed polymer-drug conjugate comprised of polyethylene glycol-maleimide (mPEG-MAL, 30000 Da) as a carrier, doxorubicin (DOX) as an anticancer drug and N-acetyl glucosamine (NAG) as a targeting moiety as well as penetration enhancer. Doxorubicin has a potent and promising anticancer activity; however, severe cardiotoxicity limits its application in cancer treatment. By modifying DOX in PEG-NAG-DOX prodrug conjugate, we aimed to eliminate this limitation. In vivo anticancer efficacy of the conjugate was evaluated using BDF mice-induced skin melanoma model by i.v. administration of DOX conjugates. Anticancer efficacy studies were done by comparing tumour volume, body weight, organ index and percent survival rate of the animals. Tumour suppression achieved by PEG-NAG-DOX at the cumulative dose of 7.5 mg/kg was two-fold better than that achieved by DOX solution. Also, the survival rate for PEG-NAG-DOX conjugate was >70% as compared to <50% survival rate for DOX solution. In addition, toxicity studies and histopathological studies revealed that while maintaining its cytotoxicity towards tumour cells, PEG-NAG-DOX conjugate showed no toxicities to major organs. Therefore, PEG-NAG-DOX conjugate can be suggested as a desirable candidate for targeted cancer therapy.

Nanoparticle impact on innate immune cell pattern-recognition receptors and inflammasomes activation

Nanotechnology-based strategies can dramatically impact the treatment, prevention and diagnosis of a wide range of diseases. Despite the unprecedented success achieved with the use of nanomaterials to address unmet biomedical needs and their particular suitability for the effective application of a personalized medicine, the clinical translation of those nanoparticulate systems has still been impaired by the limited understanding on their interaction with complex biological systems. As a result, unexpected effects due to unpredicted interactions at biomaterial and biological interfaces have been underlying the biosafety concerns raised by the use of nanomaterials. This review explores the current knowledge on how nanoparticle (NP) physicochemical and surface properties determine their interactions with innate immune cells, with particular attention on the activation of pattern-recognition receptors and inflammasome. A critical perspective will additionally address the impact of biological systems on the effect of NP on immune cell activity at the molecular level. We will discuss how the understanding of the NP-innate immune cell interactions can significantly add into the clinical translation by guiding the design of nanomedicines with particular effect on targeted cells, thus improving their clinical efficacy while minimizing undesired but predictable toxicological effects.

Poly(phosphorhydrazone) dendrimers: yin and yang of monocyte activation for human NK cell amplification applied to immunotherapy against multiple myeloma

Human natural killer (NK) cells play a key role in anti-cancer and anti-viral immunity, but their selective amplification in vitro is extremely tedious to achieve and remains one of the most challenging problems to solve for efficient NK cell-based immuno-therapeutic treatments against malignant diseases. Here we report that, when added to ex vivo culture of peripheral blood mononuclear cells from healthy volunteers or from cancer patients with multiple myeloma, poly (phosphorhydrazone) dendrimers capped with amino-bis(methylene phosphonate) end groups enable the efficient proliferation of NK cells with anti-cancer cytotoxicity in vivo. We also show that the amplification of the NK population relies on the preliminary activation of monocytes in the framework of a multistep cross-talk between monocytes and NK cells before the proliferation thereof. Thus poly(phosphorhydrazone) dendrimers represent a novel class of extremely promising drugs to develop NK-cell based anti-cancer therapies.

Glucosamine-anchored doxorubicin-loaded targeted nano-niosomes: pharmacokinetic, toxicity and pharmacodynamic evaluation

BACKGROUND

Efficacy of anticancer drug is limited due to non-selectivity and toxicities allied with the drug; therefore the heart of the present work is to formulate drug delivery systems targeted selectively towards cancer cells with minimal toxicity to normal cells.

PURPOSE

Targeted drug delivery system of doxorubicin (DOX)-loaded niosomes using synthesized N-lauryl glucosamine (NLG) as a targeting ligand.

METHODS

NLG-anchored DOX niosomes were developed using ethanol injection method.

RESULTS

Developed niosomes had particle size <150 nm and high entrapment efficiency ∼90%. In vivo pharmacokinetics exhibited long circulating nature of targeted niosomes with improved bioavailability, which significantly reduced CL and Vd than DOX solution and non-targeted niosomes (35 fold and 2.5 fold, respectively). Tissue-distribution study and enzymatic assays revealed higher concentration of DOX solution in heart while no toxicity to major organs with developed targeted niosomes was observed. Solid skin melanoma tumor model in mice manifested the commendable targeting potential of targeted niosomes with significant reduction in tumor volume and high % survival rate without drop in body weight in comparison with DOX solution and non-targeted niosomes of DOX.

CONCLUSION

The glucosamine-anchored DOX-loaded targeted niosomes showed its potential in cancer targeted drug therapy with reduced toxicity. Abbreviations ALT alanine transaminase CL clearance CPK creatinine phosphokinase DOX doxorubicin EDC.HCL ethyl carbidimide hydrochloride GLUT glucose transporter GSH glutathione S-transferase LDH lactate dehydrogenase LHRH luteinizing hormone-releasing hormone MDA malonaldehyde NHS N-hydroxy succinimide NLG N-lauryl glucosamine NTAR DoxNio non-targeted doxorubicin niosomes PBS phosphate buffer saline RGD argynyl glycyl aspartic acid SGOT serum glutamate oxaloacetate transaminase SGPT serum glutamate pyruvate transaminase SOD superoxide dismutase TAR DoxNio targeted doxorubicin niosomes Vd volume of distribution.

Glyconanomaterials for biosensing applications

Nanomaterials constitute a class of structures that have unique physiochemical properties and are excellent scaffolds for presenting carbohydrates, important biomolecules that mediate a wide variety of important biological events. The fabrication of carbohydrate-presenting nanomaterials, glyconanomaterials, is of high interest and utility, combining the features of nanoscale objects with biomolecular recognition. The structures can also produce strong multivalent effects, where the nanomaterial scaffold greatly enhances the relatively weak affinities of single carbohydrate ligands to the corresponding receptors, and effectively amplifies the carbohydrate-mediated interactions. Glyconanomaterials are thus an appealing platform for biosensing applications. In this review, we discuss the chemistry for conjugation of carbohydrates to nanomaterials, summarize strategies, and tabulate examples of applying glyconanomaterials in in vitro and in vivo sensing applications of proteins, microbes, and cells. The limitations and future perspectives of these emerging glyconanomaterials sensing systems are furthermore discussed.

Nkrp1 family, from lectins to protein interacting molecules

The C-type lectin-like receptors include the Nkrp1 protein family that regulates the activity of natural killer (NK) cells. Rat Nkrp1a was reported to bind monosaccharide moieties in a Ca²⁺-dependent manner in preference order of GalNac > GlcNAc >> Fuc >> Gal > Man. These findings established for rat Nkrp1a have been extrapolated to all additional Nkrp1 receptors and have been supported by numerous studies over the past two decades. However, since 1996 there has been controversy and another article showed lack of interactions with saccharides in 1999. Nevertheless, several high affinity saccharide ligands were synthesized in order to utilize their potential in antitumor therapy. Subsequently, protein ligands were introduced as specific binders for Nkrp1 proteins and three dimensional models of receptor/protein ligand interaction were derived from crystallographic data. Finally, for at least some members of the NK cell C-type lectin-like proteins, the “sweet story” was impaired by two reports in recent years. It has been shown that the rat Nkrp1a and CD69 do not bind saccharide ligands such as GlcNAc, GalNAc, chitotetraose and saccharide derivatives (GlcNAc-PAMAM) do not directly and specifically influence cytotoxic activity of NK cells as it was previously described.

Collagen-induced arthritis: severity and immune response attenuation using multivalent N-acetyl glucosamine

Rheumatoid arthritis is an autoimmunity leading to considerable impairment of quality of life. N-acetyl glucosamine (GlcNAc) has been described previously as a potent modulator of experimental arthritis in animal models and is used for osteoarthritis treatment in humans, praised for its lack of adverse effects. In this study we present a comprehensive immunological analysis of multivalent GlcNAc-terminated glycoconjugate (GC) application in the treatment of collagen-induced arthritis (CIA) and its clinical outcome. We used immunohistochemistry and FACS to describe conditions on the inflammation site. Systemic and clinical effects were evaluated by FACS, cytotoxicity assay, ELISA, cytometric bead array (CBA), RT-PCR and clinical scoring. We found reduced inflammatory infiltration, NKG2D expression on NK and suppression of T, B and antigen-presenting cells (APC) in the synovia. On the systemic level, GCs prevented the activation of monocyte- and B cell-derived APCs, the rise of TNF-α and IFN-γ levels, and subsequent type II collagen (CII)-specific IgG2a formation. Moreover, we detected an increase of anti-inflammatory IL-4 mRNA in the spleen. Similar to the synovia, the GCs caused a significant reduction of NKG2D-expressing NK cells in the spleen without influencing their lytic function. GCs effectively postponed the onset of arthritic symptoms, reduced their severity and in 18% (GN8P) and 31% (GN4C) of the cases completely prevented their appearance. Our data prove that GlcNAc glycoconjugates prevent the inflammatory response, involving proinflammatory cytokine rise, APC activation and NKG2D expression, leading to the attenuation of clinical symptoms. These results support the glycobiological approach to the treatment of collagen-induced arthritis/rheumatoid arthritis (CIA/RA) as a way of bringing new prospects for more effective therapeutic interventions.

Re-evaluation of the involvement of NK cells and C-type lectin-like NK receptors in modulation of immune responses by multivalent GlcNAc-terminated oligosaccharides

Recognition of glycosylation patterns is one of the basic features of innate immunity. Ability of C-type lectin-like receptors such as NKR-P1 to bind saccharide moieties has become recently a controversial issue. In the present study, binding assay with soluble fluorescently labeled recombinant rat NKR-P1A and mouse NKR-P1C proteins revealed apparently no affinity to the various neoglycoproteins. Lack of functional linkage between NKR-P1 and previously described saccharide binder was supported by the fact, that synthetic N-acetyl-D-glucosamine octabranched dendrimer on polyamidoamine scaffold (GN8P) did not change gene expression of NKR-P1 isoforms in C57BL/6 and BALB/c mice divergent in the NK gene complex (both in vitro and in vivo). Surprisingly, N-acetyl-D-glucosamine-coated tetrabranched polyamido-amine dendrimer specifically binds to NKT cells and macrophages but not to NK cells (consistently with changes in cytokine patterns). Despite the fact that GN8P has been tested as an immunomodulator in anti-cancer treatment animal models for many years, surprisingly no changes in cytokine profiles in serum relevant to anti-cancer responses using B16F10 and CT26 harboring mouse strains C57BL/6 and BALB/c are observed. Our results indicate possible indirect involvement of NK cells in GN8P mediated immune responses.

Glycopolymer probes of signal transduction

Glycans are key participants in biological processes ranging from reproduction to cellular communication to infection. Revealing glycan roles and the underlying molecular mechanisms by which glycans manifest their function requires access to glycan derivatives that vary systematically. To this end, glycopolymers (polymers bearing pendant carbohydrates) have emerged as valuable glycan analogs. Because glycopolymers can readily be synthesized, their overall shape can be varied, and they can be altered systematically to dissect the structural features that underpin their activities. This review provides examples in which glycopolymers have been used to effect carbohydrate-mediated signal transduction. Our objective is to illustrate how these powerful tools can reveal the molecular mechanisms that underlie carbohydrate-mediated signal transduction.