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The development of a facile cysteine-directed S-glycosylation strategy would facilitate the intensive investigation of the effect of glycosylation on protein translational modification. Herein, we ...

Previous study found that the solvent extraction efficiency of lipid in microalgae could be greatly improved by washing algae cells before the second time extraction. Based on the "organic solvents–water–organic solvents" method, this research further studied the effect of four solvent systems (acetone, chloroform/methanol, chloroform/methanol/water, dichloromethane/methanol), two types of water treatment (vortex and ultrasonic), three water treatment time gradient (0 s, 30 s, 120 s) on the lipid extraction at three different microalgae growth stages (3rd day, 5th day, 9th day). The results show that the combination of water treatment type, treatment time and solvent is very important to the efficiency of lipid extraction. The total lipid extracted was generally increased by 10–30% after water treatment. Especially under the condition of 120 s vortex water treatment with dichloromethane/methanol as extraction solvent, the total lipid extracted increased by 61.14%. In addition, microalgae cells at different culture stages had different sensitivity to water treatment. In this study, under the combination of chloroform/methanol/water as extraction solvent and vortex water treatment for 120 s, the highest lipid yield was obtained on the ninth day of cell culture, which accounts 47.88% of the cell dry weight (478 mg/g cell dry weight). The changes of cell morphology and structure after water treatment were studied by scanning electron microscope, and it was found that water treatment could seriously destroy the cell membrane damaged by solvent, thus promoting the release of lipids. This study further optimizes the "solvent–water–solvent" lipid extraction method, which neither produces impurities nor damages the lipid quality, and can reduce the amount of organic solvent applied in the classical lipid extraction method with the same lipid yield, so it has a broad application prospect.

Rapid diagnosis and vaccine development are critical to prevent the threat posed by viruses. However, rapid tests, such as colloidal gold assays, yield false-negative results due to the low quantities of viruses; moreover, conventional virus purification, including ultracentrifugation and nanofiltration, is multistep and time-consuming, which limits laboratory research and commercial development of viral vaccines. A rapid virus enrichment and purification technique will improve clinical diagnosis sensitivity and simplify vaccine production. Hence, we developed the surface-glycosylated microbeads (glycobeads) featuring chemically synthetic glycoclusters and reversible linkers to selectively capture the influenza virus. The surface plasmon resonance (SPR) evaluation indicated broad spectrum affinity of S-linked glycosides to various influenza viruses. The magnetic glycobeads were integrated into clinical rapid diagnosis, leading to a 30-fold lower limit of detection. Additionally, the captured viruses can be released under physiological conditions, delivering purified viruses with >50% recovery and without decreasing their native infectivity. Notably, this glycobead platform will facilitate the sensitive detection and continuous one-step purification of the target virus that contributes to future vaccine production.

Globo H is a tumor-associated carbohydrate antigen (TACA), which serves as a valuable target for antitumor vaccine or cancer immunotherapies. However, most TACAs are T-cell-independent, and they cannot induce powerful immune response due to their poor immunogenicity. To address this problem, herein, several Globo H analogues with modification on the N-acyl group were prepared through a preactivation-based glycosylation strategy from the non-reducing end to the reducing end. These modified Globo H derivatives were then conjugated with carrier protein CRM197 to form glycoconjugates as anticancer vaccine candidates, which were used in combination with adjuvant glycolipid C34 for immunological studies. The immunological effects of these synthetic vaccine candidates were evaluated on Balb/c mice. The results showed that the fluorine-modified N-acyl Globo H conjugates can induce higher titers of IgG antibodies that can recognize the naturally occurring Globo H antigen on the surface of cancer cells and can eliminate cancer cells in the presence of a complement, indicating the potential of these synthetic glycoconjugates as anticancer vaccine candidates.

A new glycosylation method promoted by visible light with 3,5-dimethoxyphenyl glycoside as the donor was developed. This protocol delivers both O-glycosides and N-glycosides in moderate to excellent yields using a wide range of O-nucleophiles and nucleobases as the glycosyl acceptors.

Carbohydrates play important roles in life science, but their synthesis is always hampered by their complicated chemical structures. Scientists have never stopped trying to solve the problem of glycan synthesis from various aspects. Here a brief overview of recent progress in glycan synthesis, including chemical approaches, chemoenzymatic approaches, and automated synthesis, will be discussed, focusing on the efficiency of new glycosylation methods, the stereoselectivity of coupled products, and their applications in the assembly of complex glycan chains.

The Keap1 (Kelch-like ECH-associated protein 1)-Nrf2 (nuclear factor erythroid 2-related factor 2)-ARE (antioxidant response element) pathway is the major defending mechanism against oxidative stresses, and directly disrupting the Keap1-Nrf2 protein-protein interaction (PPI) has been an attractive strategy to target oxidative stress-related diseases, including cardiovascular diseases. Here, we describe the design, synthesis, and structure-activity relationships (SARs) of indoline-based compounds as potent Keap1-Nrf2 PPI inhibitors. Comprehensive SAR analysis and thermodynamics-guided optimization identified 19a as the most potent inhibitor in this series, with an IC50 of 22 nM in a competitive fluorescence polarization assay. Further evaluation indicated the proper drug-like properties of 19a. Compound 19a dose-dependently upregulated genes and protein level of Nrf2 as well as its downstream markers and showed protective effects against lipopolysaccharide-induced injury in both H9c2 cardiac cells and mouse models. Collectively, we reported here a novel indoline-based Keap1-Nrf2 PPI inhibitor as a potential cardioprotective agent.

A novel transformation from rhamnose-type C-glycosides to 2-cyclopentenones is described. With the promotion of fluoroboric acid, C-glycosides underwent ring opening and subsequent Nazarov cyclization to afford 2-cyclopentenones in good to excellent yields. The solvent and the concentration of acid are crucial to the yield of this transformation.

We report a novel and highly stereoselective electro-2-deoxyglycosylation from glycals. This method features excellent stereoselectivity, scope, and functional-group tolerance. This process can also be applied to the modification of a wide range of natural products and drugs. Furthermore, a scalable synthesis of glycosylated podophyllotoxin and a one-pot trisaccharide synthesis through iterative electroglycosylations were achieved.

Prenatal stress (PNS) has a prolonged and adverse effect on offspring, leading to a significantly increased vulnerability to developing depression in their later life. Traditional therapies have delayed onset and limited efficacy; thus, it remains an urgent need to find novel medications with fast-onset and high-efficacy potentials. Crocin, with its structure clearly examined, has shown antidepressant-like effects. However, few studies extensively investigated its effect especially in mice exposed to PNS. Using an established PNS model, we tested whether crocin could have a rapid and persistent antidepressant-like effect in PNS mice. Growth hormone secretagogue receptor (GHSR) and phosphoinositide 3-kinase (PI3K) inhibitors were used to test their effects in antidepressant-like effect of crocin. Hippocampal GHSR-PI3K signaling was examined both in PNS mice treated with a single dose of crocin and in combination of GHSR inhibitor. PNS mice showed depression-like behaviors at juvenile and adulthood, and crocin induced an instant and persistent antidepressant-like response in PNS mice in a dose-dependent manner. Moreover, crocin increased the expression of hippocampal synaptic plasticity-associated proteins through the restoration of GHSR-PI3K signaling. Inhibitions of both GHSR and PI3K abolished the effect of crocin in alleviating depressive-like behaviors. More importantly, GHSR inhibitor JMV2959 blocked the enhanced expression of hippocampal plasticity-related proteins induced by crocin. The present study demonstrated that crocin induced a fast-onset and prolonged antidepressant effect in PNS mice and suggested that GHSR-PI3K signaling may play a key role in crocin's effect at least partially by a restoration of hippocampal synaptic plasticity-associated proteins.

Terminal α-2,6-sialylation of N-glycans is a humanized glycosylation that affects the properties and efficacy of therapeutic glycoproteins. Fc di-sialylation (a biantennary N-glycan with two α-2,6-linked sialic acids) of IgG antibodies imparts them with enhanced anti-inflammatory activity and other roles. However, the microheterogeneity of N-glycoforms presents a challenge for therapeutic development. Therefore, controlled sialylation has drawn considerable attention, but direct access to well-defined di-sialylated antibodies remains limited. Herein, a one-pot three-enzyme protocol was developed by engineering a bacterial sialyltransferase to facilitate the modification of therapeutic antibodies with N-acetylneuraminic acid or its derivatives towards optimized glycosylation. To overcome the low proficiency of bacterial sialyltransferase in antibody remodeling, the Photobacterium sp. JT-ISH-224 α-2,6-sialyltransferase (Psp2,6ST) was genetically engineered by terminal truncation and site-directed mutagenesis based on its protein crystal structure. With the optimized reaction conditions and using activity-based screening of various Psp2,6ST variants, a truncated mutant Psp2,6ST (111-511)-His6 A235M/A366G was shown to effectively improve the catalytic efficiency of antibody di-sialylation. Herceptin and the donor substrate promiscuity allow the introduction of bioorthogonal modifications of N-acetylneuraminic acid into antibodies for site-specific conjugation. 2-AB hydrophilic interaction chromatography analysis of the released N-glycans and intact mass characterization confirmed the high di-sialylation of Herceptin via the optimized one-pot three-enzyme reaction. This study established a versatile enzymatic approach for producing highly di-sialylated IgG antibodies. It provides new insights into engineering bacterial sialyltransferase for adaptation to the enzymatic glycoengineering of therapeutic antibodies and the glycosite-specific conjugation of antibodies.

The C-glycosylation of C-nucleophiles including allyltrimethylsilane, silyl enol ethers and phenols with N-(glycosyloxy)acetamides as glycosyl donors has been realized. This protocol provides a convenient and practical route for the synthesis of alkyl C-glycosides and aryl 2-deoxy-β-C-glycosides under mild reaction conditions.

The synthesis of tumor-associated KH-1 antigen core nonasaccharide was achieved. All key glycosidic linkages were efficiently constructed by photo-induced glycosylation. The success of this total synthesis provides an example for the preparation of complex oligosaccharides using light-driven glycosylation reactions.

We demonstrated 3D-printed photoactive composites for light sensors. The composites consist of semiconducting polymer nanowires dispersed in an insulating polymer matrix through a thermo- or photocuring process. The nanowires formed percolated networks for charge-carrier collection at a very low nanowire volume concentration. Photodetectors had been fabricated with such composites and obtained a low leakage current density of 25 nA cm–2, a large conductivity change of 18025 times upon light irradiation (1 sun), and a high specific detectivity of 4.5 × 1010 Jones. The composite precursors before curing had been used as paints on different surfaces including wood, cardboard, and glass fiber cloth to create photoactive coatings on these surfaces. The precursors had also been used for 3D printing to create photoactive structures with a mechanical modulus of 4 GPa and an ultimate strength of 36 MPa.

Although macrophage migration inhibitory factor (MIF) is known to have antioxidant property, the role of MIF in cardiac fibrosis has not been well understood. We found that MIF was markedly increased in angiotension II (Ang-II)-infused mouse myocardium. Myocardial function was impaired and cardiac fibrosis was aggravated in Mif-knockout (Mif-KO) mice. Functionally, overexpression of MIF and MIF protein could inhibit the expression of fibrosis-associated collagen (Col) 1a1, COL3A1 and α-SMA, and Smad3 activation in mouse cardiac fibroblasts (CFs). Consistently, MIF deficiency could exacerbate the expression of COL1A1, COL3A1 and α-SMA, and Smad3 activation in Ang-II-treated CFs. Interestingly, microRNA-29b-3p (miR-29b-3p) and microRNA-29c-3p (miR-29c-3p) were down-regulated in the myocardium of Ang-II-infused Mif-KO mice but upregulated in CFs with MIF overexpression or by treatment with MIF protein. MiR-29b-3p and miR-29c-3p could suppress the expression of COL1A1, COL3A1 and α-SMA in CFs through targeting the pro-fibrosis genes of transforming growth factor beta-2 (Tgfb2) and matrix metallopeptidase 2 (Mmp2). We further demonstrated that Mif inhibited reactive oxygen species (ROS) generation and Smad3 activation, and rescued the decrease of miR-29b-3p and miR-29c-3p in Ang-II-treated CFs. Smad3 inhibitors, SIS3 and Naringenin, and Smad3 siRNA could reverse the decrease of miR-29b-3p and miR-29c-3p in Ang-II-treated CFs. Taken together, our data demonstrated that the Smad3-miR-29b/miR-29c axis mediates the inhibitory effect of macrophage migration inhibitory factor on cardiac fibrosis.

Glycans have been hot topics in recent years due to their exhibition of numerous biological activities. However, the heterogeneity of their natural source and the complexity of their chemical synthesis impede the progress in their biological research. Thus, the development of glycan assembly strategies to acquire plenty of structurally well-defined glycans is an important issue in carbohydrate chemistry. In this review, the latest advances in glycan assembly strategies from concepts to their applications in carbohydrate synthesis, including chemical and enzymatic/chemo-enzymatic approaches, as well as solution-phase and solid-phase/tag-assisted synthesis, are summarized. Furthermore, the automated glycan assembly techniques are also outlined.

Carbohydrates play essential roles in various physiological and pathological processes. Trifluoromethylated compounds have wide applications in the field of medicinal chemistry. Herein, we report a practical and efficient trifluoromethylation of glycals by an electrochemical approach using CF3SO2Na as the trifluoromethyl source and MnBr2 as the redox mediator. A variety of trifluoromethylated glycals bearing different protective groups are obtained in 60-90% yields with high regioselectivity. The successful capture of a CF3 radical indicates that a radical mechanism is involved in this reaction.

Bergenin, which is isolated from Bergenia species, exhibits various pharmacological properties. In the search for new types of immunosuppressants, a series of bergenin derivatives were designed and synthesized, and their immunosuppressive effects were evaluated by the CCK-8 assay. The experimental data demonstrated that compounds 7 and 13 showed the strongest inhibition effects on mouse splenocyte proliferation (IC(50) = 3.52 and 5.39 μM, respectively). Further studies revealed that the inhibitory effect may come from the suppression of both IFN-γ and IL-4 cytokines. Alkylated derivatives of bergenin with n-hexyl and n-heptyl on the two phenolic hydroxyl groups showed better inhibitory activities. The hydrophobicity of bergenin derivatives, the configuration of the 4-OH in bergenin, and the ability to form hydrogen bonds of the substituents on the C-4 position are important to the immunosuppressive activity. This work proved that the modifications of bergenin may represent a new route to the discovery of a new class of immunosuppressive agents.

Although copper-nitrene has been extensively studied as a versatile active species in various transformations, asymmetric reactions involving copper-nitrene have been limited to the aziridination of olefins. Herein, we report the novel copper-nitrene-catalyzed desymmetric oxaziridination reaction of cyclic diketones with alkyl azides and the subsequent rearrangement of the resulting highly active intermediate, which produces a synthetically challenging chiral bicyclic lactam containing a quaternary carbon center. This procedure not only enriches the copper-nitrene-catalyzed asymmetric reactions, but also provides an alternative strategy to address the inherent challenges of catalytic asymmetric Schmidt reactions. This unique reaction could inspire the investigation of novel copper-nitrene-catalyzed asymmetric transformations and their reaction mechanisms.

Mycobacterial arabinogalactan (AG) is an essential cell wall component of mycobacteria and a frequent structural and bio‐synthetical target for anti‐tuberculosis (TB) drug development. Here, we report that mycobacterial AG is recognized by galectin‐9 and exacerbates mycobacterial infection. Administration of AG‐specific aptamers inhibits cellular infiltration caused by Mycobacterium tuberculosis (Mtb) or Mycobacterium bovis BCG, and moderately increases survival of Mtb‐infected mice or Mycobacterium marinum‐infected zebrafish. AG interacts with carbohydrate recognition domain (CRD) 2 of galectin‐9 with high affinity, and galectin‐9 associates with transforming growth factor β‐activated kinase 1 (TAK1) via CRD2 to trigger subsequent activation of extracellular signal‐regulated kinase (ERK) as well as induction of the expression of matrix metalloproteinases (MMPs). Moreover, deletion of galectin‐9 or inhibition of MMPs blocks AG‐induced pathological impairments in the lung, and the AG‐galectin‐9 axis aggravates the process of Mtb infection in mice. These results demonstrate that AG is an important virulence factor of mycobacteria and galectin‐9 is a novel receptor for Mtb and other mycobacteria, paving the way for the development of novel effective TB immune modulators., Arabinogalactan is a virulence factor of mycobacteria. Binding of galectin‐9 to mycobacterial arabinogalactan triggers matrix metalloproteinases via TAK1‐ERK signaling, which promotes mycobacterial infection and increases lung injury.

Globo H is a tumor-associated carbohydrate antigen (TACA), which serves as a valuable target for antitumor vaccine or cancer immunotherapies. However, most TACAs are T-cell-independent, and they cannot induce powerful immune response due to their poor immunogenicity. To address this problem, herein, several Globo H analogues with modification on the N-acyl group were prepared through a preactivation-based glycosylation strategy from the non-reducing end to the reducing end. These modified Globo H derivatives were then conjugated with carrier protein CRM197 to form glycoconjugates as anticancer vaccine candidates, which were used in combination with adjuvant glycolipid C34 for immunological studies. The immunological effects of these synthetic vaccine candidates were evaluated on Balb/c mice. The results showed that the fluorine-modified N-acyl Globo H conjugates can induce higher titers of IgG antibodies that can recognize the naturally occurring Globo H antigen on the surface of cancer cells and can eliminate cancer cells in the presence of a complement, indicating the potential of these synthetic glycoconjugates as anticancer vaccine candidates.

Aims Circular RNAs (circRNAs) are involved in gene regulation in a variety of physiological and pathological processes. The present study aimed to investigate the effect of circRNA_000203 on cardiac hypertrophy and the potential mechanisms involved. Methods and results CircRNA_000203 was found to be up-regulated in the myocardium of Ang-II-infused mice and in the cytoplasma of Ang-II-treated neonatal mouse ventricular cardiomyocytes (NMVCs). Enforced expression of circRNA_000203 enhances cell size and expression of atrial natriuretic peptide and β-myosin heavy chain in NMVCs. In vivo, heart function was impaired and cardiac hypertrophy was aggravated in Ang-II-infused myocardium-specific circRNA_000203 transgenic mice (Tg-circ203). Mechanistically, we found that circRNA_000203 could specifically sponge miR-26b-5p, -140-3p in NMVCs. Further, dual-luciferase reporter assay showed that miR-26b-5p, -140-3p could interact with 3′-UTRs of Gata4 gene, and circRNA_000203 could block the above interactions. In addition, Gata4 expression is transcriptionally inhibited by miR-26b-5p, -140-3p mimic in NMVCs but enhanced by over-expression of circRNA_000203 in vitro and in vivo. Functionally, miR-26b-5p, -140-3p, and Gata4 siRNA, could reverse the hypertrophic growth in Ang-II-induced NMVCs, as well as eliminate the pro-hypertrophic effect of circRNA_000203 in NMVCs. Furthermore, we demonstrated that NF-κB signalling mediates the up-regulation of circRNA_000203 in NMVCs exposed to Ang-II treatment. Conclusions Our data demonstrated that circRNA_000203 exacerbates cardiac hypertrophy via suppressing miR-26b-5p and miR-140-3p leading to enhanced Gata4 levels., Graphical Abstract Graphical Abstract

An efficient and novel methodology to access phenolic glycosides has been established by using copper-mediated coupling reaction of aryl boronic acids with hemiacetals. The reaction takes place normally in the presence of Cu(OAc)2 (1.0 equiv.) and pyridine (2.0 equiv.) at 40 °C. This protocol distinguishes itself by wide substrate scope, operational simplicity and giving rise to a myriad of phenolic glycosides in good to excellent yields.

The fabrication of wafer-scale multilayers molybdenum disulfide (MoS2) induced by sulfurizing molybdenum (Mo) seed layer could compatible with traditional semiconductor process but the random growth orientations especially the vertical aligned structures lead to the unreliability for electronic devices thus hindered their wide application. Here, we utilize multi-step heating (MH) sulfurization method to regulate the sulfurization rate and diffusion rate of thermal sulfur vapor, thus realize the fabrication of MoS2 nanofilms with wafer-level uniformity and based on this, we integrate back-gate field-effect transistor (FET) arrays with an average hole mobility of 0.9cm2 V−1 s−1 and high device yield (~98%) which illustrate the reliable electrical-performance among the device arrays and the high quality of the as-fabricated MoS2 nanofilms. Therefore, we believe our efforts could pave the way for fabricating wafer-scale transition metal dichalcogenides (TMDCs) nanofilms with high uniformity and promoting their application for the integration of electronics/optoelectronics.

A new glycosylation protocol based on 2′-benzoylphenyl glycosides has been developed. These glycosyl donors could be rapidly activated by TfOH at room temperature. The donors are readily available. The reaction exhibited a broad substrate scope and coupled products were obtained in high yields.

Background: Ca2+ plays an important role in the regulation of vasoconstriction. Ca2+ signaling is regulated by a number of Ca2+-handling proteins. However, whether differences in Ca2+ handling affect the regulation of vasoconstriction in different arteries remains elusive. Objective: To determine whether differences in Ca2+ handling affect the response to vasoconstrictors in different arteries. Methods: Arterial ring contraction was measured using a Multi Myograph System. Vascular smooth muscle cells (VSMCs) were digested with type 2 collagenase in DMEM, then intracellular calcium concentration was measured with the Ca2+ probe fluo-4/AM in the isolated cells. Calcium-related proteins were assayed by Western blotting. Results: Phenylephrine did not induce ­coronary arterial contraction. There were differences in ­5-hydroxytryptamine, 9,11-dideoxy-11a,9a-epoxymethano-prostaglandin F2a, and endothelin 1-induced vasoconstriction in different solutions between coronary and renal arteries. Vasoconstrictions in the presence of Bay K8644 were stronger in coronary than in renal arteries. Store-operated calcium (SOC) channels could mediate Ca2+ influx in VSMCs of both groups. SOC channels did not participate in the contraction of coronary arteries. In addition, there were significant differences in the expressions of receptors and ion channels between the two groups. Conclusions: Ca2+ handling contributed to the different responses to vasoconstrictors between coronary and renal arteries.

Summary of main observation and conclusion The N-glycans attached to some chloroviruses comprise a hyperbranched core structure without precedent. We are interested in the chemical synthesis of the hexasaccharide attached to ATCV-1 (Acanthocystis turfacea Chlorella virus 1) for its distinct structure. After exploring four routes, the target hexasaccharide 2 was successfully synthesized for the first time in overall 10% yield over 8 steps from thioglycoside building blocks. This synthetic protocol is characterized by the three-component one-pot glycosylation and the regioselective glycosylation reactions. The disclosed synthetic approach to this new type of N-glycans will facilitate the in-depth understanding of their biological functions.

The chirality of supramolecular polymeric materials is subtly affected by a delicate balance among various non-covalent interactions, the details of which are inadequately understood. Now, a fine balance of intermolecular interactions, including closed-shell metal-metal, dispersive and electrostatic interactions, is used to direct the delicate orientation of monomeric building blocks, thereby achieving the successful preparation of different nanostructures with distinct supramolecular chirality. Moreover, kinetically trapped and thermodynamically stable aggregates were monitored over time in the supramolecular polymerization of cationic PtII complexes. The dynamic self-assembly process can be successfully controlled by modifying the counteranion and solvent composition. A chiral doping approach can also be used to induce the chirality of an achiral PtII complex at the supramolecular level.

An efficient Cr(VI) adsorbent, mesoporous amine-functionalized silica (NH-SiO2), was successfully synthesized within 2 h by a facile one-step route under room temperature and aqueous solution. The structure properties of the obtained materials were characterized by N2 adsorption-desorption isotherm, XRD, TEM, and FT-IR. The Cr(VI) removal performance was investigated by batch experiment. It was found that Cr(VI) removal performance was dependent on solution pH, and the removal efficiency is above 90% for initial pH in the range of 1.0–4.0. The adsorption process was obeyed by pseudo-second-order model, and the equilibrium adsorption data were fitted well by Langmuir model. The maximum monolayer adsorption capacity was 205.76 mg/g at pH 2.0, which was larger than that of traditional two-step tri-amine-functionalized MCM-41. Additionally, high selectivity was exhibited in NH-SiO2 for removal Cr(VI) from co-presence anions Cl−, NO3−, PO43−, SO42−, and SiO32−. Furthermore, the spent NH-SiO2 could be regenerated by 0.005 M NaOH, and Cr(VI) removal is above 92% after NH-SiO2 recycled four. From the analyzed results of adsorption energy, FT-IR, and XPS, the electrostatic attraction between protonated amine group and HCrO4− was the mainly adsorption mechanism. And then some adsorbed Cr(VI) was reduced to low toxicity Cr(III) on the adsorbent surface by electron transfer from nitrogen in –NBr group to Cr(VI).

Carbohydrates play important roles in many biological processes. However, the lack of resources of structurally-defined carbohydrates and their weak immunogenicity have always restricted the development of chemical glycobiology especially carbohydrate-based vaccines. The progress in chemical synthesis of carbohydrates and glycoconjugates has greatly promoted the development of carbohydrate-based vaccines including antibacterial vaccines, anti-tumor vaccines and anti-HIV vaccines. The use of one-pot glycosylation strategy and solid-phase glycosylation strategy is able to synthesize oligosaccharides and even polysaccharides more effectively than before. Glycoconjugates produced by combining the carbohydrate antigens and proper protein carriers improve the immunogenicity of carbohydrates. This review covers the general methods and strategies of carbohydrate chemical synthesis, and the recent development of carbohydrate-based vaccines, and also summarizes related work of our group, hoping to offer readers better understanding of chemical glycobiology especially carbohydrate-based vaccines.

This study was conducted to estimate the protective effect of Cyanidin-3-glucoside (C3G) on myocardial ischemia-reperfusion (IR) injury and to explore its mechanism. The rats were subjected to left anterior descending ligation and perfusion surgery. In vitro experiments were performed on H9c2 cells using the oxygen-glucose deprivation/reoxygenation (OGD/R) model. The results showed the administration of C3G reduced the infarction area, mitigated pathological alterations, inhibited ST segment elevation, and attenuated oxidative stress and ferroptosis-related protein expression. C3G also suppressed the expressions of USP19, Beclin1, NCOA4, and LC3II/LC3I. In addition, treatment with C3G relieved oxidative stress, downregulated LC3II/LC3I, reduced autophagosome number, downregulated TfR1 expression, and upregulated the expressions of FTH1 and GPX4 in OGD/R-induced H9c2 cells. C3G could inhibit the protein levels of USP19 and LC3II. C3G promoted K11-linked ubiquitination of Beclin1. Further evidence that C3G reduced ferroptosis and ameliorated myocardial I/R injury was demonstrated with the ferroptosis promoter RSL3. Taken together, C3G could be a potential agent to protect myocardium from myocardial I/R injury.

α-Cyperone (Cy) is a major active compound of Cyperus rotundus that has various pharmacological activities. But whether Cy possesses antidepressant effect is unknown. In this study, we exposed mice to chronic unpredictable mild stress (CUMS) with or without intervention with Cy. Our results showed that Cy significantly improved the depressive phenotypes in sucrose preference test, tail suspension test and forced swimming test. Meanwhile, increased SIRT3 expression, reduced ROS production and activated NF-κB signal were detected in the hippocampus of mice. NLRP3 inflammasome related proteins including NLRP3, ASC, Caspase-1, IL-1β, IL-18 and GSDMD-N were downregulated after Cy administration. Synaptic proteins including Synapsin-1 and PSD-95 and dendritic spine density were improved after Cy treatment. Moreover, the protective effects of Cy in CUMS mice were compromised when co-administrated with SIRT3 inhibitor 3-TYP. Taken together, these findings suggested that Cy has therapeutic potential for treating depression and that this antidepressant effect may be attributed to SIRT3 stimulated neuroplasticity enhancement by suppressing NLRP3 inflammasome.

A series of novel pyrano[2, 3-d]trizaole compounds were synthesized and their α-glucosidase inhibitory activities were evaluated by in vitro enzyme assay. The experimental data demonstrated that compound 10f showed up to 10-fold higher inhibition (IC5074.0 ± 1.3 μmol·L-1) than acarbose. The molecular docking revealed that compound 10f could bind to α-glucosidase via the hydrophobic, π-π stacking, and hydrogen bonding interactions. The results may benefit further structural modifications to find new and potent α-glucosidase inhibitors.

Reversibly altering endogenous protein levels are persistent issues. Herein, we designed photoswitchable azobenzene-proteolysis targeting chimeras (Azo-PROTACs) by including azobenzene moieties between ligands for the E3 ligase and the protein of interest. Azo-PROTACs are light-controlled small-molecule tools for protein knockdown in cells. The light-induced configuration change can switch the active state to induce protein degradation activity, which can be reversely controlled by light exposure in intact cells. We compared the protein degradation abilities of Azo-PROTACs with different configurations and linker lengths. Using the stable form with the best degradation ability against the BCR-ABL fusion and ABL proteins in myelogenous leukemia K562 cells, we showed that Azo-PROTAC combines the potent protein knockdown and facile cell uptake properties of the small-molecule PROTAC with a reversible photoswitchability, offering a promising chemical knockdown strategy based on the light-induced reversible on/off properties.

Background Cyanidin (CY) is one of the most abundant anthocyanidins found in red-purple diet sources such as grapes, blueberries and purple corns. CY has been proven to exhibit a wide range of biological functions including antioxidant, antiviral, anticarcinogenic and anti-inflammatory properties. Purpose This study investigated the anti-depressive activity of CY and its related mechanism. Methods In the behavioral tests, CY-related effects on depressive symptoms were evaluated. Then the changes in PI3K/AKT/FOXG1/FGF-2 signaling and adult neurogenesis including doublecortin (DCX+) cell number, dendritic length, secondary and third dendrites number in the hippocampus were investigated by Immunofluorescence and Western blot analyses. PI3K antagonist LY 294,002 was used to verify the unique impact of PI3K/AKT/FoxG1/FGF-2 signaling on CY-related antidepressant efficacy. Results CY grossly reversed CUMS-induced behavioral defects, The DCX+ cell number and protein levels increased in CUMS mice receiving CY administration. LY 294,002 successfully blocked CY-induced improvements in depressive behaviors, neurogenesis, and protein levels in CUMS mice. Conclusion The findings demonstrated that CY was efficacious in alleviating depression-like symptoms, which was dependent on PI3K/AKT/FoxG1/FGF-2 signaling-modulated neurogenesis enhancement.

Background. The aim of this study was to investigate the effects of human umbilical cord mesenchymal stem cell activated by curcumin (hUC-MSCs-CUR) on Parkinson’s disease (PD). hUC-MSCs can differentiate into many types of adult tissue cells including dopaminergic (DA) neurons. CUR could protect DA neurons from apoptosis induced by 6-hydroxydopamine (6-OHDA). Therefore, we used the hUC-MSCs activated by CUR for the treatment of PD in an animal model. Methods. The hUC-MSCs-CUR was transplanted into the MPTP-induced PD mouse models via the tail vein. We found that hUC-MSCs-CUR significantly improved the motor ability, increased the tyrosine hydroxylase (TH), dopamine (DA), and Bcl-2 levels, and reduced nitric oxide synthase, Bax, and cleaved caspase 3 expression in PD mice. The supernatant of hUC-MSCs-CUR (CM-CUR) was used to stimulate the SH-SY5Y cellular model of PD; cell proliferation, differentiation, TH, and neuronal-specific marker microtubular-associated protein 2 (MAP2) expressions were examined. Results. Our data showed that CM-CUR significantly promoted cell proliferation and gradually increased TH and MAP2 expression in SH-SY5Y PD cells. The beneficial effects could be associated with significant increase of rough endoplasmic reticulum in the hUC-MSCs-CUR, which secretes many cytokines and growth factors beneficial for PD treatment. Conclusions. Transplantation of hUC-MSCs-CUR could show promise for improving the motor recovery of PD.

It is important to find more effective and safer immunosuppressants, because clinically used immunosuppressive agents have significant side effects. A series of N-substituted iminosugar derivatives were designed and synthesized, and their immunosuppressive effects were evaluated by the CCK-8 assay. The results revealed that iminosugars 10 e and 10 i, that is, (3R,4S)-1-(4-heptyloxylphenylethyl)pyrrolidine-3,4-diol and (3R,4S)-1-[2-(2-chloro-4-(p-tolylthio)-phenyl-1-yl)ethyl]pyrrolidine-3,4-diol, respectively, exhibited the strongest inhibitory effects on mouse splenocyte proliferation (IC50 =2.16 and 2.48 μm, respectively), whereas the iminosugars containing an amide group near the hydrophilic head (compounds 10 j-n) exhibited no inhibitory effects. Further studies revealed that the inhibitory effects on splenocyte proliferation may have come from the suppression of both IFN-γ and IL-4 cytokines. Our results suggest that synthetic iminosugars, especially compounds 10 e and 10 i, hold potential as immunosuppressive agents.

Hypertension is a main risk factor for atrial fibrillation, but the direct effects of hydrostatic pressure on the atrial fibrosis are still unknown. The present study investigated whether hydrostatic pressure is responsible for atrial fibrosis, and addressed a potential role of the Smad pathway in this pathology. Biochemical assays were used to study regulation and expression of fibrotic factors in spontaneously hypertensive rats (SHRs) and Wistar rats, and in cardiac fibroblasts (CFs) cultured under standard (0 mmHg) and elevated (20, 40 mmHg) hydrostatic pressure. Levels of atrial fibrosis and protein expression of fibrotic factors Col-1A1/-3A1, TGF-β1, and MMP-2 in SHRs' left atrial tissues were higher than those in Wistar rats. Exposure to elevated pressure was associated with the proliferation of CFs. The protein expression of Col-1A1/-3A1, TGF-β1, and MMP-2 in CFs was also up-regulated in a pressure-dependent manner. The proliferation of CFs and increased expressions of fibrotic markers induced by elevated hydrostatic pressure could be reversed by the Smad3 inhibitor naringenin. The activation of Smad3 pathway was also stimulated by elevated hydrostatic pressure. These results demonstrate that CF secretory function and proliferation can be up-regulated by exposure to elevated pressure, and that Smad3 may modulate CF activation induced by high hydrostatic pressure.

Background: As reported EGFR is a sialoglycoprotein with tyrosine kinase activity involved in control of cellular survival, multiplication, differentiation and metastasis. Dysregulation or aberrant expression of EGFR has been implicated in cell transformation and having oncogenic roles in a number of human cancers. Therefore EGFR has become a significant target for developing targeted therapy for cancer. Methods: A novel series of indole-3-carboxamide derivatives as EGFR inhibitors were designed, synthesized and evaluated for the anticancer activity in vitro against three EGFR high-expressed cancer cell lines (A549, HeLa, and SW480), one EGFR low-expressed cell line (HepG2) and one human liver normal cell line (HL7702) by MTT assay. Results: The target compounds 6c, 6f, 6i, 6j, 6l, 6r, 6u and 6x exhibited potent anticancer activities against the three tested cancer cell lines and weak cytotoxic effects on HepG2, which imply that the target compounds are probably effective in inhibiting EGFR. And they also did not show measurable activities in HL7702, which imply the target compounds are likely to overcome the nonspecific toxicity against normal cells. Particularly, the target compound 6x indicated equal to the positive control erlotinib. In addition, molecular docking studies demonstrated the target compound 6x may be the potential inhibitor to EGFR. Conclusion: A new EGFR inhibitor scaffold and a preliminary discussion on their SARs provide promising opportunities to guide further research on indole-3-carboxamide derivatives as novel anticancer agents.

Vi antigen is the capsular polysaccharide of Salmonella typhi, which can cause typhoid fever. With the increasing threat of antiboitic resistance, vaccination against Salmonella typhi is a preferred way to prevent this disease. Chemical synthesis of fragments of Vi antigen is in urgent need for the development of structure-homogeneous and quality-controlled oligosaccharide vaccines. However, it is extremely challenging to synthesize large oligosaccharide fragments of Vi antigen owing to the exclusive α-1,4-linkage of polyaminogalacturonates. Herein, a series of Vi oligosaccharides ranging from pentamer to octamer were efficiently prepared using 2,3-N,O-oxazolidinone protected glycosides as building blocks based on the preactivation protocol. The heptasaccharide and octasaccharide fragments were synthesized for the first time. The competitive ELISA evaluation suggested that the hexasaccharide might be the minimum epitope of Vi antigen, which provides a significant guidance for the future development of Vi oligosaccharide vaccines.

A metal-free and light-promoted approach to the synthesis of N -9 alkylated purine nucleoside derivatives, via a CF 3 radical triggered radical relay pathway, has been developed. Purine nucleoside derivatives were prepared regioselectively in good to high yields. Photosensitizers and metals are free in this transformation. Visible light or even sunlight can be used as the source of light for the reactions.

X-ray detectors are demonstrated using composite films of lead-free Cs2AgBiBr6 halide double perovskite embedded in a polymer matrix as the X-ray photoconductors. Polymers with hydroxyl functional groups greatly improve the uniformity of the composite films, and large area dense films are obtained using a simple drop-casting process. X-ray detectors based on the composite films exhibit a sensitivity of 40 μC Gyair−1 cm−2, comparable to the reported sensitivity using Cs2AgBiBr6 single crystals. Such detectors can also tolerate a 5% tensile/compressive strain in the composite films without performance degradation. Pixelated X-ray detectors fabricated on the same composite film can realize X-ray imaging and resolve a proof-of-concept geometric pattern.

Necrosis is a form of cell death, which is related to various serious diseases such as cardiovascular disease, cancer, and neurodegeneration. Necrosis-avid agents (NAAs) selectively accumulated in the necrotic tissues can be used for imaging and/or therapy of related diseases. The aim of this study was to preliminarily investigate necrosis avidity of 131I-evans blue (131I-EB) and its mechanism. The biodistribution of 131I-EB at 24 h after intravenous administration showed that the radioactivity ratio of necrotic to viable tissue was 3.41 in the liver and 11.82 in the muscle as determined by γ counting in model rats. Autoradiography and histological staining displayed preferential uptake of 131I-EB in necrotic tissues. In vitro nuclear extracts from necrotic cells exhibited 82.3% of the uptake in nuclei at 15 min, as well as 79.2% of the uptake at 2 h after 131I-EB incubation. The DNA binding study demonstrated that evans blue (EB) has strong binding affinity with calf-thymus DNA (CT-DNA) (Ksv=5.08×105 L/(mol/L)). Furthermore, the accumulation of 131I-EB in necrotic muscle was efficiently blocked by an excess amount of unlabeled EB. In conclusion, 131I-EB can not only detect necrosis by binding the DNA released from necrotic cells, but also image necrotic tissues generated from the disease clinically., Graphical abstract In the present study, we demonstrated that 131I-evens blue (EB) could specifically bind to necrotic tissues image necrosis in living animals. Furthermore, the necrosis targeting mechanism of EB might be attributed to its binding to exposed DNA in necrotic areas.fx1

A practical and efficient synthesis of phosphatidylinositol pentamannoside (PIM5) was achieved based on a five-component one-pot sequential glycosylation protocol with exclusive regio- and stereo-selectivity. Two regioselective sequential glycosylations on inositol and p-tolyl thioglycosides as the sole type of building blocks made this protocol to avoid the tedious protective group manipulations. This synthetic strategy provides access to other important glycolipids with similar structures.