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Go, S.

Publications and source records attributed to Go, S..

7 recordsLinked to original sources

Reverse genetics system for emerging tick-borne orthonairovirus highlights dispensable N-terminal region of Gn associated with replication in tick vectors

A growing number of emerging and re-emerging tick-borne orthonairoviruses belonging to the Sulina and Tamdy genogroups have recently been identified in association with febrile diseases in East Asia. Yezo virus (YEZV) is one such viruses and is genetically distinct from well-characterized Crimean-Congo hemorrhagic fever virus. Orthonairovirus glycoproteins (Gn and Gc) expressed from a single glycoprotein precursor (GPC) gene mediate interaction with host cells, yet the organization and functions of the YEZV glycoproteins remain largely undefined. To characterize YEZV glycoproteins in the context of infection, we developed a reverse genetics system that enables recovery of recombinant YEZV entirely from cloned cDNAs. The recombinant wild-type virus exhibited growth properties comparable to those of the parental isolate in vitro and maintained pathogenicity in vivo. Proteomic analysis of purified virus particles produced in mammalian cells showed that peptide coverage of GPC-derived products began at residue 69. We therefore used the reverse genetics system to examine the functional importance of the GPC subregion upstream of residue 69. A mutant with a deletion of GPC residues 28 to 68 (rYEZV GPC{Delta}28-68), which retained the predicted signal peptide, was successfully recovered, suggesting that this subregion is dispensable for producing infectious virus. rYEZV GPC{Delta}28-68 propagated at levels comparable to those of the wild-type virus in mammalian cells and exhibited similar pathogenicity in a mouse model. Interestingly, the mutant reached lower viral titers in tick-derived ISE6 cells and in ticks in vivo, suggesting that this N-terminal subregion may contribute to virus replication in ticks. Together, these findings demonstrate the utility of the newly established reverse genetics system for dissecting the functions of the YEZV glycoproteins in mammalian and tick systems.

microbiology↗

High-precision Biomedical Text Corpora for Multi-Entity Recognition: A CoDiet study

We present here five biomedical, multi-entity corpora that can be used as benchmarks for named-entity recognition (NER), targeted to literature on metabolic syndrome. The CoDiet-Gold corpus contains annotations for 500 full-text publications and 348,406 annotations. It is divided into CoDiet-Gold-public (450 documents) and CoDiet-Gold-private (50 documents). Each document was independently annotated by two human experts, with disagreements fully adjudicated by a third expert. The CoDiet-Electrum corpus (2,998,273 annotations) contains 4,423 publications that were annotated using case-insensitive matching of the surface forms with punctuation ignored, found in CoDiet-Gold-public. Finally, for the same 4,423 documents, two fully machine annotated corpora CoDiet-Bronze (2,938,738 annotations) and CoDiet-Silver (2,298,988 annotations), were created by utilising existing NER algorithms to annotate these. These corpora contain categories (organisms, disease, genes, proteins, metabolites) that add depth to existing corpora, as well as new categories that do not appear in other corpora (food, dietary methods, sample types, computational methods, study methodology, population characteristics, data types, and microbiome).

bioinformatics↗

Retention of DLK1 in the endoplasmic reticulum identifies roles for EGF domain-specific O-glycans in the secretory pathway

In the endoplasmic reticulum (ER), O-glycosylation by O-fucose, O-glucose, and O-GlcNAc occurs in the epidermal growth factor-like (EGF) domains of secreted or transmembrane glycoproteins. Previous studies focusing on Notch receptors have revealed the pivotal role of these O-glycans in the cell surface expression of Notch or secretion of truncated Notch fragments. Although it has been demonstrated that O-fucose, O-glucose, and O-GlcNAc stabilize individual EGF domains, their role in the secretory pathway after the completion of the folding process remains unexplored. In this study, we used delta-like 1 homolog (DLK1) containing six consecutive EGF domains as a model glycoprotein to investigate the role of EGF domain-specific O-glycans in the secretory pathway. Semi-quantitative site-specific glycoproteomics of recombinantly expressed DLK1 revealed multiple O-fucose and O-glucose modifications in addition to an unusual EOGT-dependent O-hexose modification. Consistent with the results of the secretion assay, inactivation of the glycosyltransferases modifying O-fucose and O-glucose, but not the newly identified O-hexose, perturbed the transport of DLK1 from the ER during retention using the selective hooks (RUSH) system. Importantly, the absence of O-fucose did not result in an apparent loss of O-glucose modification within the same EGF domain, and vice versa. Given that protein O-fucosyltransferase 1 and protein O-glucosyltransferase 1 activities depend on the folded state of the EGF domains, O-glycans affected DLK1 transport independently of the folding process required for O-glycosylation in the ER. These findings highlight the distinct roles of O-glycans in facilitating the transport of DLK1 from the ER to the cell surface.

biochemistry↗

Tissue-resident NK cells support survival in pancreatic cancer through promotion of cDC1-CD8T activity

The immunosuppressive microenvironment in pancreatic ductal adenocarcinoma (PDAC) prevents tumor control and strategies to restore anti-cancer immunity (i.e. by increasing CD8 T cell activity) have had limited success. Here we demonstrate how inducing localized physical damage using ionizing radiation (IR) unmasks the benefit of immunotherapy by increasing tissue-resident NK (trNK) cells that support CD8 T activity. Our data confirms that targeting mouse orthotopic PDAC tumors with IR together with CCR5 inhibition and PD1 blockade reduces E-cadherin positive tumor cells by recruiting a hypoactive NKG2D-ve NK population, phenotypically reminiscent of trNK cells, that supports CD8 T cell involvement. We show an equivalent population in human PDAC cohorts that represents immunomodulatory trNK cells that could similarly support CD8 T cell levels in a cDC1-dependent manner. Importantly, a trNK signature associates with survival in PDAC and solid malignancies revealing a potential beneficial role for trNK in improving adaptive anti-tumor responses and supporting CCR5i/PD1 and IR-induced damage as a novel therapeutic approach.

cancer biology↗

Opposite regulation of glycogen metabolism by cAMP produced in the cytosol and at the plasma membrane

Cyclic AMP is produced in cells by two different types of adenylyl cyclases: at the plasma membrane by the transmembrane adenylyl cyclases (tmACs, ADCY1[~]ADCY9) and in the cytosol by the evolutionarily more conserved soluble adenylyl cyclase (sAC, ADCY10). By employing high-resolution extracellular flux analysis to study glycogen breakdown in real time, we show here thatcAMP regulates glycogen metabolism in opposite directions depending on its location of synthesis within cells. While the canonical tmAC-cAMP-PKA axis promotes glycogenolysis, we demonstrate that the non-canonical sAC-cAMP-Epac1 signalling suppresses glycogenolysis in a variety of cell types. Our findings demonstrate the importance of cAMP microdomain organization in glycogen metabolism and reveal a novel role of sAC in energy metabolism during glucose deprivation.

biochemistry↗

Non-canonical regulation of glycogenolysis and the Warburg phenotype by soluble adenylyl cyclase

Cyclic AMP is produced in cells by two very different types of adenylyl cyclases: the canonical transmembrane adenylyl cyclases (tmACs, ADCY1[~]9) and the evolutionarily more conserved soluble adenylyl cyclase (sAC, ADCY10). While the role and regulation of tmACs is well documented, much less is known of sAC in cellular metabolism. We demonstrate here that sAC is an acute regulator of glycolysis, oxidative phosphorylation and glycogen metabolism, tuning their relative bioenergetic contributions. Suppression of sAC activity leads to aerobic glycolysis, enhanced glycogenolysis, decreased oxidative phosphorylation, and an elevated cytosolic NADH/NAD+ ratio, resembling the Warburg phenotype. Importantly, we found that glycogen metabolism is regulated in opposite directions by cAMP depending on its location of synthesis and downstream effectors. While the canonical tmAC-cAMP-PKA axis promotes glycogenolysis, we identify a novel sAC-cAMP-Epac1 axis that suppresses glycogenolysis. These data suggest that sAC is an autonomous bioenergetic sensor that suppresses aerobic glycolysis and glycogenolysis when ATP levels suffice. When the ATP level falls, diminished sAC activity induces glycogenolysis and aerobic glycolysis to maintain energy homeostasis.

biochemistry↗

Type-2 CD8+ T lymphocytes responsive to PGD2 and LTE4 in severe eosinophilic asthma

The functions and in vivo roles of type-2 CD8+ T cells in humans have not been well defined and this cell type has been largely overlooked in models of disease. We investigated this in the context of severe asthma with persistent airway eosinophilia - a phenotype associated with high exacerbation risk and responsiveness to type-2 cytokine-targeted therapies. In two independent cohorts we show that, in contrast to Th2 cells, type-2 cytokine-secreting CD8+CRTH2+ (Tc2) cells are enriched in blood and airways in severe eosinophilic asthma. Concentrations of prostaglandin D2 (PGD2) and cysteinyl leukotriene E4 (LTE4) are also increased in the airways of the same group of patients. In vitro PGD2 and LTE4 function synergistically to trigger Tc2 cell recruitment and activation in a TCR-independent manner. These lipids regulate diverse genes in Tc2 cells inducing type-2 cytokines and many other pro-inflammatory cytokines and chemokines which could contribute to eosinophilia. These findings are consistent with an important innate-like role for human Tc2 cells in severe eosinophilic asthma and suggest a potential target for therapeutic intervention in this and other diseases.

immunology↗