What comes next in glycobiology.

Glycans, with their variable compositions and highly dynamic conformations, vastly expand the heterogeneity of whatever factor or cell they are attached to. These properties make them crucial contributors to biological function and organismal health and also very difficult to study. That may be changing as we look to the future of glycobiology.

Prediction of Human Pharmacokinetics of E0703, a Novel Radioprotective Agent, Using Physiologically Based Pharmacokinetic Modeling and an Interspecies Extrapolation Approach.

E0703, a new steroidal compound optimized from estradiol, significantly increased cell proliferation and the survival rate of KM mice and beagles after ionizing radiation. In this study, we characterize its preclinical pharmacokinetics (PK) and predict its human PK using a physiologically based pharmacokinetic (PBPK) model. The preclinical PK of E0703 was studied in mice and Rhesus monkeys. Asian human clearance (CL) values for E0703 were predicted from various allometric methods. The human PK profiles of E0703 (30 mg) were predicted by the PBPK model in Gastro Plus software 9.8 (SimulationsPlus, Lancaster, CA, USA). Furthermore, tissue distribution and the human PK profiles of different administration dosages and forms were predicted. The 0.002 L/h of CL and 0.005 L of Vss in mice were calculated and optimized from observed PK data. The plasma exposure of E0703 was availably predicted by the CL using the simple allometry (SA) method. The plasma concentration-time profiles of other dosages (20 and 40 mg) and two oral administrations (30 mg) were well-fitted to the observed values. In addition, the PK profile of target organs for E0703 exhibited a higher peak concentration (Cmax) and AUC than plasma. The developed E0703-PBPK model, which is precisely applicable to multiple species, benefits from further clinical development to predict PK in humans.

A Semisynthesis Platform for the Efficient Production and Exploration of Didemnin-Based Drugs.

Plitidepsin (or dehydrodidemnin B), an approved anticancer drug, belongs to the didemnin family of cyclic depsipeptides, which are found in limited quantities in marine tunicate extracts. Herein, we introduce a new approach that integrates microbial and chemical synthesis to generate plitidepsin and its analogues. We screened a Tistrella strain library to identify a potent didemnin B producer, and then introduced a second copy of the didemnin biosynthetic gene cluster into its genome, resulting in a didemnin B titer of approximately 75 mg/L. Next, we developed two straightforward chemical strategies to convert didemnin B into plitidepsin, one of which involved a one-step synthetic route giving over 90 % overall yield. Furthermore, we synthesized 13 new didemnin derivatives and three didemnin probes, enabling research into structure-activity relationships and interactions between didemnin and proteins. Our study highlights the synergistic potential of biosynthesis and chemical synthesis in overcoming the challenge of producing complex natural products sustainably and at scale.

Target protein deglycosylation in living cells by a nanobody-fused split O-GlcNAcase.

O-linked N-acetylglucosamine (O-GlcNAc) is an essential and dynamic post-translational modification that is presented on thousands of nucleocytoplasmic proteins. Interrogating the role of O-GlcNAc on a single target protein is crucial, yet challenging to perform in cells. Herein, we developed a nanobody-fused split O-GlcNAcase (OGA) as an O-GlcNAc eraser for selective deglycosylation of a target protein in cells. After systematic cellular optimization, we identified a split OGA with reduced inherent deglycosidase activity that selectively removed O-GlcNAc from the desired target protein when directed by a nanobody. We demonstrate the generality of the nanobody-fused split OGA using four nanobodies against five target proteins and use the system to study the impact of O-GlcNAc on the transcription factors c-Jun and c-Fos. The nanobody-directed O-GlcNAc eraser provides a new strategy for the functional evaluation and engineering of O-GlcNAc via the selective removal of O-GlcNAc from individual proteins directly in cells.

Icaritin Derivative IC2 Induces Cytoprotective Autophagy of Breast Cancer Cells via SCD1 Inhibition.

Breast cancer is one of the most prevalent malignancies and the leading cause of cancer-associated mortality in China. Icaritin (ICT), a prenyl flavonoid derived from the Epimedium Genus, has been proven to inhibit the proliferation and stemness of breast cancer cells. Our previous study demonstrated that IC2, a derivative of ICT, could induce breast cancer cell apoptosis by Stearoyl-CoA desaturase 1 (SCD1) inhibition. The present study further investigated the mechanism of the inhibitory effects of IC2 on breast cancer cells in vitro and in vivo. Our results proved that IC2 could stimulate autophagy in breast cancer cells with the activation of adenosine monophosphate (AMP)-activated protein kinase (AMPK) signaling and mitogen-activated protein kinase (MAPK) signaling. Combination treatment of the AMPK inhibitor decreased IC2-induced autophagy while it markedly enhanced IC2-induced apoptosis. In common with IC2-induced apoptosis, SCD1 overexpression or the addition of exogenous oleic acid (OA) could also alleviate IC2-induced autophagy. In vivo assays additionally demonstrated that IC2 treatment markedly inhibited tumor growth in a mouse breast cancer xenograft model. Overall, our study was the first to demonstrate that IC2 induced cytoprotective autophagy by SCD1 inhibition in breast cancer cells and that the autophagy inhibitor markedly enhanced the anticancer activity of IC2. Therefore, IC2 was a potential candidate compound in combination therapy for breast cancer.

Development of a novel phosphoramidite-selenide ligand for Pd-catalyzed asymmetric allylic substitution.

A novel chiral P,Se-heterodonor ligand has been designed and prepared through an efficient and simple operation. This ligand can be successfully applied to Pd-catalyzed asymmetric allylic substitution with C- and N-nucleophiles, producing a diverse range of chiral allylic products in high yields and enantioselectivities (up to 99% yield and 95% ee).

Mechanisms of Pb(II) coprecipitation with natrojarosite and its behavior during acid dissolution.

Lead (Pb) coprecipitation with jarosite is common in natural and engineered environments, such as acid mine drainage (AMD) sites and hydrometallurgical industry. Despite the high relevance for environmental impact, few studies have examined the exact interaction of Pb with jarosite and the dissolution behavior of each phase. In the present work, we demonstrate that Pb mainly interacts with jarosite in four modes, namely incorporation, occlusion, physically mixing, and chemically mixing. For comparison, the four modes of Pb-bearing natrojarosite were synthesized and characterized separately. Batch dissolution experiments were undertaken on these synthetic Pb-bearing natrojarosites under pH 2 to simulate the AMD environments. The introduction of Pb decreases the final Fe releasing efficiency of jarosite-type compounds from 18.18% to 3.45%-5.01%, showing a remarkable inhibition of their dissolution. For Pb releasing behavior, PbSO4 dissolves in preference to Pb-substituted natrojarosite, i.e., (Na, Pb)-jarosite, which primarily results in the sharp increase of Pb releasing concentration (> 40 mg/L). PbSO4 occlusion by jarosite-type compounds can significantly reduce the release of Pb. The results of this study could provide useful information regarding Fe and Pb cycling in acidic natural and engineered environments.

Writing and erasing O-GlcNAc from target proteins in cells.

O-linked N-acetylglucosamine (O-GlcNAc) is a widespread reversible modification on nucleocytoplasmic proteins that plays an important role in many biochemical processes and is highly relevant to numerous human diseases. The O-GlcNAc modification has diverse functional impacts on individual proteins and glycosites, and methods for editing this modification on substrates are essential to decipher these functions. Herein, we review recent progress in developing methods for O-GlcNAc regulation, with a focus on methods for editing O-GlcNAc with protein- and site-selectivity in cells. The applications, advantages, and limitations of currently available strategies for writing and erasing O-GlcNAc and future directions are also discussed. These emerging approaches to manipulate O-GlcNAc on a target protein in cells will greatly accelerate the development of functional studies and enable therapeutic interventions in the O-GlcNAc field.

IL-38 Alleviates Inflammation in Sepsis in Mice by Inhibiting Macrophage Apoptosis and Activation of the NLRP3 Inflammasome.

Interleukin- (IL-) 38 is an emerging cytokine with multiple functions involved in infection and immunity. However, the potential role of IL-38 in the host immune response during sepsis remains elusive. Herein, we investigated if macrophages in septic mice express IL-38, the molecular mechanisms behind its expression, and the downstream effects of its expression. In mouse peritoneal macrophages, lipopolysaccharide (LPS) upregulated IL-38 and its receptor IL-36R, and the resulting IL-38 shifted macrophages from a M1 to M2 phenotype. Moreover, exposure to IL-38 alone was sufficient to inhibit macrophage apoptosis and LPS-driven activation of the NOD-, LRR-, and pyrin domain-containing 3 (NLRP3) inflammasome. These effects were partly abrogated by IL-38 downregulation. In septic mice, IL-38 markedly lowered serum concentrations of proinflammatory cytokines and greatly improved survival. Conversely, IL-38 blockade aggravated their mortality. Collectively, these findings present IL-38 as a potent immune modulator that restrains the inflammatory response by suppressing macrophage apoptosis and activation of the NLRP3 inflammasome. IL-38 may help protect organs from sepsis-related injury.

Effect of Interleukin-36ß on Activating Autophagy of CD4+CD25+ Regulatory T cells and Its Immune Regulation in Sepsis.

BACKGROUND: CD4+CD25+ regulatory T cells (Tregs) play an essential role in sepsis-induced immunosuppression. How, the effects of interleukin 36 (IL-36) cytokines on CD4+CD25+ Tregs and their underlying mechanism(s) in sepsis remain unknown. METHODS: Our study was designed to investigate the impacts of IL-36 cytokines on murine CD4+CD25+ Tregs in presence of lipopolysaccharide (LPS) and in a mouse model of sepsis induced by cecal ligation and puncture (CLP). IL-36-activated autophagy was evaluated by autophagy markers, autophagosome formation, and autophagic flux. RESULTS: IL-36α, IL-36ß, and IL-36γ were expressed in murine CD4+CD25+ Tregs. Stimulation of CD4+CD25+ Tregs with LPS markedly up-regulated the expression of these cytokines, particularly IL-36ß. IL-36ß strongly suppressed CD4+CD25+ Tregs under LPS stimulation and in septic mice challenged with CLP, resulting in the amplification of T-helper 1 response and the proliferation of effector T cells. Mechanistic studies revealed that IL-36ß triggered autophagy of CD4+CD25+ Tregs. These effects were significantly attenuated in the presence of the autophagy inhibitor 3-methyladenine or Beclin1 knockdown. In addition, early IL-36ß administration reduced the mortality rate in mice subjected to CLP. Depletion of CD4+CD25+ Tregs before the onset of sepsis obviously abrogated IL-36ß-mediated protection against sepsis. CONCLUSIONS: These findings suggest that IL-36ß diminishes the immunosuppressive activity of CD4+CD25+ Tregs by activating the autophagic process, thereby contributing to improvement of the host immune response and prognosis in sepsis.

Interleukin-38 protects against sepsis by augmenting immunosuppressive activity of CD4+ CD25+ regulatory T cells.

Naturally occurring CD4+ CD25+ regulatory T cells (Tregs) are required to limit immune-induced pathology and to maintain homeostasis during the early-phase of sepsis. This study aimed to investigate the role of interleukin (IL)-38, a newly described member of the IL-1 cytokine family, in mediated immune response of CD4+ CD25+ Tregs in sepsis. Here, we provide evidence that expressions of IL-38 and its receptor were detected in murine CD4+ CD25+ Tregs. Stimulation of CD4+ CD25+ Tregs with LPS markedly up-regulated the expression of IL-38. Treatment with rmIL-38 dramatically enhanced the immunosuppressive activity of CD4+ CD25+ Tregs after LPS stimulation and in septic mice induced by CLP, resulting in amplification of helper T cell (Th) 2 response and reduction in the proliferation of effector T cells. These effects were robustly abrogated when anti-IL-38 antibody was administered. Administration of rmIL-38 improved the survival rate of CLP mice. In addition, CD4+ CD25+ Tregs depletion before the onset of sepsis obviously abolished IL-38-mediated protective response. These findings suggest that IL-38 enhances the immunosuppressive activity of CD4+ CD25+ Tregs, which might contribute to the improvement of host immune function and prognosis in the setting of sepsis.

Anti-inflammatory signaling through G protein-coupled receptors.

G protein-coupled receptors (GPCRs) play important roles in human physiology. GPCRs are involved in immunoregulation including regulation of the inflammatory response. Chemotaxis of phagocytes and lymphocytes is mediated to a great extent by the GPCRs for chemoattractants including myriads of chemokines. Accumulation and activation of phagocytes at the site of inflammation contribute to local inflammatory response. A handful of GPCRs have been found to transduce anti-inflammatory signals that promote resolution of inflammation. These GPCRs interact with selected metabolites of arachdonic acid, such as lipoxins, and of omega-3 essential fatty acids, such as resolvins and protectins. Despite mounting evidence for the in vivo functions of these anti-inflammatory and pro-resolving ligands paired with their respective GPCRs, the underlying signaling mechanisms have not been fully delineated. The present review summarizes what we have learned about these GPCRs, their structures and signaling pathways and the prospect of targeting these receptors for novel anti-inflammatory therapies.

MicroRNA-4461 derived from bone marrow mesenchymal stem cell exosomes inhibits tumorigenesis by downregulating COPB2 expression in colorectal cancer.

Colorectal cancer (CRC) is one of the main cause of cancer-related deaths. It's reported that bone marrow mesenchymal stem cells (BMSCs) affects tumor development through secreting exosomes. This study aims to investigate the function of BMSCs-derived exosome miR-4461 in CRC. The results of qRT-PCR showed that miR-4461 expression in DLD1, HCT116 and SW480 CRC cells and CRC tissues was lower than that in FHC cells and normal tissues, respectively. And COPB2 mRNA expression was negatively correlated with miR-4461. Western blot was used to detect COPB2 protein expression. Dual-luciferase reporter assay results revealed that miR-4461 targeted COPB2. Transwell assay and CCK-8 assay demonstrated that COPB2 knockdown inhibited HCT116 and SW480 cells proliferation, migration and invasion abilities. Furthermore, BMSCs-derived exosome miR-4461 downregulated COPB2 expression and inhibited HCT116 and SW480 cells migration and invasion. The findings demonstrated that miR-4461 could be a potential target for the diagnosis and treatment of colorectal cancer.

Enzyme-Mediated Intercellular Proximity Labeling for Detecting Cell-Cell Interactions.

Cell-cell interactions and communications play fundamental roles in life processes but remain largely uncharacterized. We developed an enzyme-mediated proximity cell labeling (EXCELL) strategy as a general method to detect and record cell-cell interactions under living conditions. EXCELL relies on an evolved Staphylococcus aureus transpeptidase sortase A variant (mgSrtA) capable of promiscuous labeling of various cell surface proteins containing a monoglycine residue at the N-terminus. Displaying mgSrtA on the surface of a cell of interest allows the labeling and detection of interacting cells in a proximity-dependent fashion.

α-Mangostin suppresses NLRP3 inflammasome activation via promoting autophagy in LPS-stimulated murine macrophages and protects against CLP-induced sepsis in mice.

BACKGROUND: The major mechanism of sepsis is immunosuppression caused by host response dysfunction. It has been found that α-Mangostin (α-M) is a potential candidate as a treatment for multiple inflammatory and immune disorders. To date, the role of α-M in host response during sepsis remains unexplored. METHODS AND RESULTS: Herein, we examined the effect of α-M on macrophages-mediated host response in the presence of lipopolysaccharide (LPS), and the vital organ function, inflammatory response, and survival rate in septic mice. In murine peritoneal macrophages, α-M induced autophagy and then inhibited LPS-stimulated NLRP3 inflammasome activation, as well as interleukin-1ß (IL-1ß) production. Moreover, α-M improved phagocytosis and killing of macrophages, and increased M2 macrophages numbers after LPS stimulation. Furthermore, in vivo experiment suggested that α-M reduced serum levels of tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), IL-1ß, alanine transaminase (ALT), aspartate transaminase (AST), and creatinine (Cr), whilst increased that of interleukin-10 (IL-10) in caecal ligation and puncture (CLP) mice. CONCLUSION: Taken together, these findings showed that α-M-mediated macrophages autophagy contributed to NLRP3 inflammasome inactivation and α-M exerted organ protection in septic mice.

Reactions of 5-Aminoisoxazoles with α-Diazocarbonyl Compounds: Wolff Rearrangement vs N-H Insertion.

A highly chemoselective reaction between 5-aminoisoxazoles and α-diazocarbonyl compounds has been described. Both Wolff rearrangement and N-H insertion products can be obtained selectively by the judicious choice of reaction conditions. In the case of the Wolff rearrangement reactions, the N-isoxazole amides are accessed as the sole products under thermal conditions. On the other hand, α-amino acid derivatives of N-isoxazolescan be obtained through N-H insertion reactions in the presence of catalytic Rh2(Oct)4. Both reactions proceed under mild reaction conditions and feature a broad substrate scope.

Successful voriconazole treatment of Talaromyces marneffei infection in an HIV-negative patient with osteolytic lesions.

Talaromyces marneffei (T. marneffei) is a dimorphic fungus that causes systemic infection in immunocompromised patients. Here, we present a case of T. marneffei infection in an immunocompetent patient with an osteolytic lesion. Diagnosis was established by fungal culture. The patient responded rapidly to intravenous voriconazole, followed by oral voriconazole. We reviewed 18 reported cases of T. marneffei infection with osteolytic lesions, which suggests a much higher rate of osteolytic lesions in immunocompetent patients than previously thought.

[Ophiopogonin D protects cardiomyocytes against ophiopogonin D'-induced injury through suppressing endoplasmic reticulum stress].

This study is aimed to investigate the intervention effect and possible mechanism of ophiopogonin D( OPD) in protecting cardiomyocytes against ophiopogonin D'( OPD')-induced injury,and provide reference for further research on toxicity difference of saponins from ophiopogonins. CCK-8 assay was used to evaluate the effect of OPD and OPD' on cell viability. The effect of OPD on OPD'-induced cell apoptosis was measured by flow cytometry. Morphologies of endoplasmic reticulum were observed by endoplasmic reticulum fluorescent probe. PERK,ATF-4,Bip and CHOP mRNA levels were detected by Real-time quantitative polymerase chain reaction( PCR) analysis. ATF-4,phosphorylated PERK and e IF2α protein levels were detected by Western blot assay. RESULTS:: showed that treatment with OPD'( 6 µmol·L-1) significantly increased the rate of apoptosis; expressions of endoplasmic reticulum stress related genes were increased. The morphology of the endoplasmic reticulum was changed. In addition,different concentrations of OPD could partially reverse the myocardial cell injury caused by OPD'. The experimental results showed that OPD'-induced myocardial toxicity may be associated with the endoplasmic reticulum stress,and OPD may modulate the expression of CYP2 J3 to relieve the endoplasmic reticulum stress caused by OPD'.

Genetically Encoded Chemical Decaging in Living Bacteria.

We report the genetically encoded chemical decaging strategy for protein activation in living bacterial cells. In contrast to the metabolically labile photocaging groups inside Escherichia coli, our chemical decaging strategy that relies on the inverse electron-demand Diels-Alder (iDA) reaction is compatible with the intracellular environment of bacteria, which can be a general tool for gain-of-function study of a given protein in prokaryotic systems. By applying this strategy for in situ activation of the indole-producing enzyme TnaA, we built an orthogonal and chemically inducible indole production pathway inside E. coli cells, which revealed the role of indole in bacterial antibiotic tolerance.

Progress and prospects of circular RNAs in Hepatocellular carcinoma: Novel insights into their function.

Hepatocellular carcinoma (HCC) is one of the most predominant subjects of liver malignancies, which arouses global concern in the recent years. Advanced studies have found that Circular RNAs (circRNAs) are differentially expressed in HCC, with its regulatory capacity in HCC pathogenesis and metastasis. However, the underlying mechanism remains largely unknown. In this review, we summarized the functions and mechanisms of those aberrantly expressed circRNAs in HCC tissues. We hope to enlighten more comprehensive studies on the detailed mechanisms of circRNAs and explore their potential values in clinic applications. It revealed that hsa_circ_0004018 can be used as a potential biomarker in HCC diagnosis, with its superior sensitivity to alpha-fetoprotein (AFP). Notably, the correlation of circRNA abundance in the proliferation of liver regeneration (LR) has recently been clarified and different circRNA profiles served as candidates for nonalcoholic steatohepatitis (NASH) diagnosis also be discussed. Therefore, the improved understanding of circRNAs in HCC pathogenesis and metastasis proposed a novel basis for the early diagnosis in HCC patients, which provides a useful resource to explore the pathogenesis of HCC.