Dynamic Distribution of Glycoconjugates During Oogenesis of Atractomorpha sinensis

The dynamic distribution of three different glycoconjugates in oocytes and follicle cells during the oogenesis of Atractomorpha sinensis were detected using biotin-labeled Peanut Agglutinin （PNA）, Soy Bean Agglutinin （SBA） and Ulex Europaeus Agglutinin I （UEA-I） lectins. The results showed that during oogenesis there was no distribution of the UEA-I receptor. The receptors of PNA and SBA were found to be dependent on developmental stage and present different distribution patterns accordingly. The binding sites of the two lectins indicated the presence of different sugars （PNA for Galβ1,3GalNAc and SBA for GalNAc） and showed considerable variation during oogenesis. PNA and SBA receptors first appeared at the oocyte growth phase, the PNA receptors then disappeared gradually and the SBA receptors exhibited the greatest expression. At the early phase of yolk formation, PNA and SBA receptors were located just at the brim of ooplasm, which was the region of vitellin formation. However at the later phase of yolk formation, neither of the two receptors was detected. In the mature egg, PNA and SBA receptors were distributed again on the vitellin membrane and the eggshell. The two receptors were also widely distributed in the follicular cells, showing similar distribution variation to the oocytes. The results indicate that the change and modification of the two receptors may be greatly related to the growth of oocytes, the preparation for yolk formation, the differentiation of follicular cells and the maturation of oocytes. The glycoconjugates on the vitellin membrane probably play important roles in sperm and egg recognition. The two lectins bound moderately or strongly to the eggshell, which indicates that the eggshell of A. sinensis contains the GalNAc and GalβGalNAc glycoproteins.

Supramolecular complex glycoconjugate vaccine generates self-enhancement effects for carbohydrate antigen delivery

Targeting delivery of tumor-associated carbohydrate antigen(TACA)-based vaccine to antigen-presenting cells(APCs)mediated by endogenous antibodies can improve the immunogenicity of TACA.However,an essential requirement of this approach is to generate high titers of endogenous antibodies in vivo through pre-immunization,which complicates the immunization procedure and may cause side effects.Herein,we report a new generation of APC-targeting TACA-based supramolecular complex vaccine,assembled by sialyl Thomsen-nouveau-bovine serum albumin-adamantine(sTn-BSA-Ada)and heptavalent rhamnose(Rha)-modifiedβ-cyclodextrin(β-CD)via host-guest interaction.The complex vaccine retained anti-Rha antibodies recruiting capability and facilitated the APCs uptake of the vaccine via the interaction of the Fc-domain with the Fc receptors on APCs.We demonstrate that direct immunization of complex vaccine elicited anti-Rha and anti-sTn specific immune response synchronously,generating a novel self-enhancement effect that can improve the antigen delivery to APCs in high efficacy.The structure-activity relationship(SAR)study proved that complex vaccine 4 with polyethylene glycol 6(PEG 6)linker in host molecule provoked a robust and specific sTn immune response comparable to the pre-immunization approach.The antisera induced by complex vaccine,either through direct immunization or pre-immunization,exhibited equal potency of cytotoxicity against the sTn expression cancer cells.This study provides a general platform for TACA-based vaccines with self-enhancement effects without the need for pre-immunization.

Spectroscopy Investigation on Conformational Transition of Tea Glycoconjugate from Green Tea

The conformational transition of a new glycoconjugate, tea glycoconjugate (TGC), was investigated by spec-troscopy techniques including circular dichroism (CD) and ultraviolet (UV) spectroscopy. The solution behaviors of TGC in the mediums of different temperature, pH value, and ions were compared. Results showed that the native conformation of TGC was partially ordered. The CD value and UV absorbance of TGC altered with the change of pH value, temperature, the addition of ions, and also accompanied order-disorder transition. Especially the condi-tions with temperature higher than the glass transition temperature (Tg=62 ℃), higher pH value or lower pH value will have the most impact on the conformation of TGC, which will destroy the hydrogen bonds between the TGC molecules. The results indicated that the outside factors play important roles on the stability of the conformation of TGC.

β-1,2-Mannan-based glycoconjugates as potential antifungal vaccines

Phosphorylated di-,tri-and tetra-saccharides ofβ-1,2-mannan antigen derived from Candida albicans(C.albicans)cell wall were synthesized and covalently conjugated with keyhole limpet hemocyanin(KLH)and human serum albumin(HSA)via a bifunctional linker under mild conditions.The semi-syntheticβ-1,2-mannoside–KLH conjugates were evaluated for the immunization of BALB/c mice.The ELISA results revealed that all three conjugates could elicit high levels of specific IgG antibodies and the acquired antisera could effectively identify theβ-1,2-mannan epitope.Furthermore,the immunofluorescence and flow cytometry assays also uncovered that the induced antibodies,especially that obtained from immunization withβ-1,2-mannotriose–KLH conjugate(1b),could bind well to fungi cell.Eventually,the structure–immunogenicity relationship analysis ofβ-mannan showed that the length of oligo-β-mannoses had a big impact on their immunogenicity andβ-1,2-mannotriose showed the strongest immunogenicity.The results suggested the great potential ofβ-1,2-mannotriose–KLH conjugate as an antifungal vaccine candidate.

Hesperetin conjugated PEGylated gold nanoparticles exploring the potential role in anti-inflammation and anti-proliferation during diethylnitrosamine-induced hepatocarcinogenesis in rats

Liver cancer is the fifth most common cancer and one of the leading causes of death in the world, and second most common cause of death in men. Natural products emerge as the most enduring approaches in the development of anticancer targeting drug. Hesperetin(HP), one of the abundant flavonoids found naturally in citrus fruits, has received considerable attention in anti-cancer promotion and progression. The present study was conducted to decipher the role of 0.5 ml hesperetin conjugated gold nanoparticles(Au-m PEG(5000)-S-HP NPs) during diethylnitrosamine(DEN)-induced hepatocarcinogenesis in male Wistar albino rats and shows the better antioxidant that possesses anti-inflammatory,anti-proliferation and anticarcinogenic properties and may modulate signaling pathways.The confirmation of polymer functionalized gold nanoparticles and drug loaded polymer gold nanoparticles were characterized by HR-TEM with EDAX, and DLS with Zeta potential techniques. The drug encapsulation efficiency and release properties were carried out in PBS at pH 7.4 for Au-mPEG(5000)-S-HP and compared with the control pure hesperetin(HP).Here, we review the role of mast cell counts, tumor necrosis factor alpha(TNF-α), transcription factor nuclear factor-κB(NF-κB), levels of glycoconjugates, proliferating cell nuclear antigen(PCNA) and argyrophilic nucleolar organizing regions, are the master regulator of inflammation and proliferation, in the development of hepatocellular injury, liver fibrosis and HCC. DEN-administered animals showed increased mast cell counts, tumor necrosis factor alpha, transcription factor nuclear factor-κB, glycoconjugates, proliferating cell nuclear antigen, and argyrophilic nucleolar organizing regions. Whereas Au-mPEG(5000)-S-HP NPs supplementation considerably suppressed all the above abnormalities. These results suggest that the Au-m PEG(5000)-S-HP NPs exhibited the better potential anticancer activity by inhibiting cell inflammation and proliferation in DEN-induced hepatocellular carcinogenesis.

5-Fluorocytosine–Sugar Conjugates for Glucose Transporter-Mediated Tumor Targeting: Synthesis, Cytotoxicity, and Cellular Uptake Mechanism

Two novel sugar-conjugated 5-fluorocytosine(5-FC)antineoplastic compounds were designed and synthesized to improve the selective drug uptake by targeting the tumor-specific glucose transporter(GLUT).The antitumor activity of these compounds was evaluated in four different human cancer cell lines:A549(human lung cancer cell line),HT29(human colorectal cancer cell line),H460(human lung cancer cell line),and PC3(human prostate cancer cell line).The sugar conjugates exhibited cytotoxicity similar to or higher than 5-FC and 1-hexylcarbamoyl-5-FC in A549,HT29,H460,and PC3.Furthermore,GLUT-mediated transport of the glycoconjugate was investigated with GLUT inhibitor-mediated cytotoxicity analysis in a GLUT-overexpressing HT29 cell line.The cell-killing potency of 5-FC glycoconjugate was found to depend significantly on the GLUT inhibitor,and the cellular uptake of molecules was regulated by GLUT-mediated transport.All the results demonstrate the potential advantages of glycoconjugation for Warburg effect-targeted drug design.

Kinetic Studies on Aniline-catalyzed Carbohydrate Oxime Formation via Real-time NMR

The authors investigated an aniline-catalyzed method to accelerate the reaction between equimolar reducing glycans and hydroxylamines. The rate-constants determined by real-time NMR were associated with the equivalence ratio of aniline rather than the concentration. Conjugates of oligosaccharide with hydroxylamine can be obtained in high efficiency at pH=5.4.

Synthesis of a Novel Type of Glycophosphate Mimics

A series of novel type of glycophosphate mimics are synthesized by Todd reaction and their structure were determined on the basis of NMR, ESI-MS.

Synthesis of Indomethacin Conjugates with D-Glucosamine

Two series of indomethacin conjugates with D-glucosamine were prepared with theobjectives of reducing ulcerogenic potency, increasing the bioavailability of indomethacin andexerting the coordinative effects on osteoarthritis. The structures of the conjugates were identifiedby H NMR and C NMR. The ester conjugates inhibited edema as potent as indomethacin. 1 13

Preliminary Study of the Lectin Receptor Expression in Adenocarcinomas of the Gastrointestinal Tract

Ten cases of gastrointestinal adenocarcinomas were histochemically investigated fortheir lectin receptors by avidin—biotin-peroxidase complex(ABC)method.Results showed thatgastric adenocarcinomas expressed more types of lectin receptors than large boweladenocarcinomas.Positive rates of Glc/Man-and GlcNAc-specific lectin receptors in these tu-mors were kigher than those of Gal/GalNAc-and Fuc-specific lectin receptors.From the stom-ach to rectum,the spectrum of the lectin receptors in pericarcinomatous tissues graduallychanged from the gastric type to the rectal type.The expression of lectin receptors ingustrointestinal adenocarcinomas was obviously different Jrom that in their correspondingpericarcinomatous tissues.The increase and decrease of lectin receptor expression,theappearance and disappearance of some types of lectin receptors as well as the change of thereceptor distribution are indirectly regulated by cellular genome.

Immunological Exploration of Helicobacter pylori Serotype O_(2) O-Antigen by Using a Synthetic Glycan Library

Helicobacter pylori(H.pylori)infection is a threat to human health.The lipopolysaccharide(LPS)O-antigen holds promise for developing vaccines.It is meaningful to explore the immunological activity of oligosaccharides with different lengths and frameshifts for antigen development.Herein,a glycan library of H.pylori O2 O-antigen containing eight fragments is constructed.After screening with anti-H.pylori O2 LPS sera and patients’sera by glycan microarray,the disaccharide HPO2G-2b and trisaccharide HPO2G-3a show strong antigenicity and then are separately conjugated with carrier protein CRM197.Both glycoconjugates elicit a robust immunoglobulin G(IgG)immune response in rabbits.The anti-HPO2G-3a IgG antibodies possess a much stronger binding affinity with the LPS and bacteria of H.pylori O2 than the anti-HPO2G-2b IgG antibodies.There is no cross-reaction between both sera IgG antibodies with LPS and bacteria of H.pylori O1,O6,and E.coli.The results demonstrate the trisaccharide HPO2G-3a is a promising candidate for H.pylori vaccine development.

Synthesis and immunological study of a glycosylated wall teichoic acid-based vaccine against Staphylococcus aureus

Staphylococcus aureus wall teichoic acids(WTAs) are attractive targets for antibacterial vaccine development. In this study, three core glycosylated WTA structure, including α-1,4-Glc NAc, β-1,4-Glc NAc andβ-1,3-Glc NAc modified ribitol phosphates containing a linker are chemically synthesized and conjugated with tetanus toxin(TT) carrier protein as vaccine candidates. In vivo immunological studies demonstrate that the synthesized glycosylated WTAs display high immunogenicity and all conjugates provoke strong immune responses and elicit high levels of specific IgG antibodies against the Glc NAc-modified WTA. Furthermore, antibodies elicited by the vaccine candidates remain the capability to recognize S. aureus cells and display significant opsonophagocytic activity to clear S. aureus. This study demonstrates that the core structure of glycosylated WTAs are effective antigens for constructing anti-S. aureus vaccines to prevent and control S. aureus infections.

Carbohydrate-based drugs launched during 2000-2021

Carbohydrates are fundamental molecules involved in nearly all aspects of lives,such as being involved in formating the genetic and energy materials,supporting the structure of organisms,constituting invasion and host defense systems,and forming antibiotics secondary metabolites.The naturally occurring carbohydrates and their derivatives have been extensively studied as therapeutic agents for the treatment of various diseases.During 2000 to 2021,totally 54 carbohydrate-based drugs which contain carbohydrate moities as the major structural units have been approved as drugs or diagnostic agents.Here we provide a comprehensive review on the chemical structures,activities,and clinical trial results of these carbohydrate-based drugs,which are categorized by their indications into antiviral drugs,antibacterial/antiparasitic drugs,anticancer drugs,antidiabetics drugs,cardiovascular drugs,nervous system drugs,and other agents.

Carboxymethyl glycoside lactone(CMGL) synthons:Scope of the method and preliminary results on step growth polymerization of α-azide-ω-alkyne glycomonomers

Carboxymethyl glycoside lactones(CMGLs) are bicyclic synthons which open readily for accessing new types of pseudo-glycoconjugates,such as sugar-amino acid hybrids,neoglycolipids,pseudodisaccharides,and membrane imaging systems.After lactone opening,free OH-2 is available for further functionalization,leading to 1,2-bisfunctionalized derivatives.This strategy is illustrated herein with new polymerizable systems of the AB type bearing both azide and alkyne functions prepared from α or β gluco-CMGL synthons.After the reaction of lactones with propargylamine,an azido group was introduced by two different sequences leading to either the 2-manno-azido or the 6-gluco-azido products.The capability of these AB monomers to undergo step growth polymerization through copper(I) catalyzed alkyne-azide cycloaddition(CuAAC) and generate glycopolytriazoles was evidenced.

Full synthesis and bioactivity evaluation of Tn-RC-529 derivative conjugates as self-adjuvanting cancer vaccines

A facile and efficient strategy was established for the construction of RC-529 and its derivatives.Four conjugates of RC-529 derivatives with Tn antigen were synthesized and all elicited strong and T celldependent immune responses in mice without requiring external adjuvants.In addition,all antisera induced by these conjugates could specifically recognize,bind to and kill Tn-overexpressing cancer cells.Thus,RC-529 shows promise as a useful platform for the development of new vaccine carriers with self-adjuvanting properties for the treatment of cancer.Moreover,preliminary structure-activity relationship analysis provides convincing support for further optimization of,and additional investigation into RC-529.

t-BuOLi Catalyzed Esterification of N-Benzyl-N-Boc-amides with Carbohydrates

Based on a strategy of ground-state destabilisation of the N—C bond,a general protocol for the esterification of amides with carbohydrates was reported.This protocol offers mild reaction conditions,excellent yields,and broad substrate compatibility,thereby demonstrating great potential for the synthesis of glycoconjugates.Additionally,this method provides an alternative approach for addressing the challenging task of esterifying sterically hindered secondary hydroxyl group of carbohydrates and paving the way for advancements in carbohydrate-based pharmaceuticals.