Altered Innate Immunity Confers Staphylococcus aureus Resistance in O-glycosylation Deficient Caenorhabditis elegans bus Mutants
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PROVIDER: PRJNA601206 | ENA |
REPOSITORIES: ENA
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Project description:The Caenorhabditis elegans bus (bacterial unswollen) mutants were isolated by their altered response to the nematode pathogen Microbacterium nematophilum. The bus-2, bus-4 and bus-17 mutants are resistant to infection by this bacterium and to infection by human pathogens Yersinia pestis and Yersinia pseudotuberculosis. Here we extend that list to Staphylococcus aureus. The bus-2, bus-4 and bus-17 mutants each harbors a defect in a different glycosyltransferase involved in O-glycosylation. Glycomics analysis of these strains reveals significant O-glycosylation defects. We further investigated the nature of bus mutant phenotypes in bus-2, bus-4 and bus-17 by gene expression analysis. Three distinct areas of altered expression were identified: 1) N- and O-glycosylation; 2) innate immune response; 3) protein folding and editing control. As expected N- and O-glycosylation gene expression was altered at key enzymatic steps. Innate immune system expression patterns were altered in a way that significantly overlapped with expression patterns seen in wild-type upon exposure to Staphylococuss aureus. Upon infection with S. aureus markers of innate immune activity increased significantly compared to wild-type. The abu/pqn genes, active in the non-canonical unfolded protein response (UPR) pathway were dramatically upregulated in bus when these mutants were exposed to the pathogen. This work demonstrates a genetic link between O-glycosylation and expression of key components of the innate immune response.
2021-01-06 | GSE143664 | GEO
Project description:Altered RNA export by SF3B1 mutants confers sensitivity to nuclear export inhibition
| PRJNA1073893 | ENA
Project description:Bladder tumours with aggressive characteristics often present microenvironmental niches marked by low oxygen levels (hypoxia) and limited glucose supply due to inadequate vascularization. The molecular mechanisms facilitating cellular adaptation to these stimuli remain largely elusive. Employing a multi-omics approach, we discovered that hypoxic and glucose-deprived cancer cells enter a quiescent state supported by mitophagy, fatty acid β-oxidation, and amino acid catabolism, concurrently enhancing their invasive capabilities. Reoxygenation and glucose restoration efficiently reversed cell quiescence without affecting cellular viability, highlighting significant molecular plasticity in adapting to microenvironmental challenges. Furthermore, cancer cells exhibited substantial perturbation of protein O-glycosylation, leading to simplified glycophenotypes with shorter glycosidic chains. Exploiting glycoengineered cell models, we established that immature glycosylation contributes to reduced cell proliferation and increased invasion. Our findings collectively indicate that hypoxia and glucose deprivation trigger cancer aggressiveness, reflecting an adaptive escape mechanism underpinned by altered metabolism and protein glycosylation, providing grounds for clinical intervention.
2025-02-12 | GSE284635 | GEO
Project description:Glycosylation is central to the localization and function of biomolecules1. We recently discovered that small RNAs undergo N-glycosylation2 at the modified RNA base 3-(3-amino-3-carboxypropyl) uridine (acp3U)3. However, the functional significance of N-glycosylation of RNAs is unknown. Here we show that the N-glycans on glycoRNAs prevent innate immune sensing of endogenous small RNAs. We found that de-N-glycosylation of cell culture-derived and circulating human and mouse glycoRNA elicited potent inflammatory responses including the production of type I interferons in a TLR3- and TLR7-dependent manner. Further, we show that N-glycans of cell surface RNAs prevent apoptotic cells from triggering endosomal RNA sensors in efferocytes, thus facilitating the non-inflammatory clearance of dead cells. Mechanistically, N-glycans conceal the hypermodified uracil base acp3U, which we identified as immunostimulatory when exposed in RNA. Consistent with this, genetic deletion of an enzyme (DTWD2) that synthesizes acp3U abrogated innate immune activation by de-N-glycosylated of small RNAs and apoptotic cells. Additionally, synthetic acp3U-containing RNAs are sufficient to trigger innate immune responses. Thus, our study has uncovered a natural mechanism by which N-glycans block RNAs from inducing acp3U-driven innate immune activation, demonstrating how glycoRNAs exist on the cell surface and in the endosomal network without inducing autoinflammatory responses.
2025-08-11 | GSE291767 | GEO
Project description:Multilevel Plasticity and Altered Glycosylation Drive Aggressiveness in Hypoxic and Glucose-Deprived Bladder Cancer Cells
| PRJNA1199976 | ENA
Project description:KIAA1324 is a transmembrane protein largely reported as a tumor suppressor and favorable prognosis marker in various cancers, including gastric cancer. In this study, we report the role of N-linked glycosylation in KIAA1324 as a functional post-translational modification (PTM). Loss of N-linked glycosylation eliminated the potential of KIAA1324 to suppress cancer cell proliferation and migration. Furthermore, we demonstrated that KIAA1324 undergoes fucosylation, a modification of the N-glycan mediated by fucosyltransferase, and inhibition of fucosylation also significantly suppressed KIAA1324-induced cell growth inhibition and apoptosis of gastric cancer cells. In addition, KIAA1324-mediated apoptosis and tumor regression were inhibited by the loss of N-linked glycosylation. RNA sequencing (RNAseq) analysis revealed that genes most relevant to the apoptosis and cell cycle arrest pathways were modulated by KIAA1324 with the N-linked glycosylation, and Gene Regulatory Network (GRN) analysis suggested novel targets of KIAA1324 for anti-tumor effects in transcription level. The N-linked glycosylation blockade decreased protein stability through rapid proteasomal degradation. The non-glycosylated mutant also showed altered localization and lost apoptotic activity that inhibits the interaction between GRP78 and caspase 7. These data demonstrate that N-linked glycosylation of KIAA1324 is essential for the suppressive role of KIAA1324 protein in gastric cancer progression and indicates that KIAA1324 may have anti-tumor effects by targeting cancer-related genes with N-linked glycosylation. In conclusion, our study suggests the PTM of KIAA1324 including N-linked glycosylation and fucosylation is a necessary factor to consider for cancer prognosis and therapy improvement.
2023-08-07 | GSE239904 | GEO
Project description:RNA N-glycosylation enables innate immune evasion and homeostatic efferocytosis
| PRJNA1235213 | ENA
Project description:Elevated N-linked glycosylation of immunoglobulin G variable regions (IgG-VN-Glyc) is an emerging molecular phenotype associated with autoimmune disorders. To test the broader specificity of elevated IgG-VN-Glyc, we studied patients with distinct subtypes of myasthenia gravis (MG), a B cell-mediated autoimmune disease. Our experimental design included adaptive immune receptor repertoire sequencing to quantify and characterize N-glycosylation sites in the global B cell receptor repertoire, proteomics to examine glycosylation patterns of the circulating IgG, and production of human-derived recombinant autoantibodies, which were studied with mass spectrometry and antigen binding assays to confirm occupation of glycosylation sites and determine whether they alter binding. We found that the frequency of IgG-VN-Glyc motifs was increased in the B cell repertoire of MG patients when compared to healthy donors. Motifs were introduced by both biased V gene segment usage and somatic hypermutation. IgG-VN-Glyc could be observed in the circulating IgG in a subset of MG patients. Autoantigen binding, by patient-derived MG autoantigen-specific monoclonal antibodies with experimentally confirmed presence of IgG-VN-Glyc, was not altered by the glycosylation. Our findings extend prior work on patterns of variable region N-linked glycosylation in autoimmunity to MG subtypes. Although occupied IgG-VN-Glyc motifs are found on MG autoantigen-specific monoclonal antibodies, they are not required for binding to the autoantigen in this disease.
2021-08-13 | GSE182038 | GEO
Project description:Much of the N-glycosylation machinery was identified decades ago, but the regulatory mechanisms influencing normal and disease states are only beginning to be discovered. Recent studies highlight a role for key metabolites and metabolic enzymes in this process, revising the view of the relationship between different metabolic pathways. Using a multi-omic approach in a zebrafish, we discovered a mechanism where O-GlcNAcylation directly influences the expression and abundance of two enzymes essential for the earliest steps of N-linked glycosylation, the nus1-encoded NgBR and Dpagt1. Here we show that phosphomannomutase (pmm2) deficiency is associated with increased levels of UDP-GlcNAc and protein O-GlcNAcylation. Biochemical studies show that O-GlcNAc modification of the NgBR and Dpagt1 increases their abundance in pmm2m/m mutants. Modulating O-GlcNAc levels, NgBR abundance or Dpagt1 activity exacerbated cartilage phenotypes in pmm2 mutants, suggesting that O-GlcNAc mediated increases in the N-glycosylation machinery protects against more severe pathology. These findings highlight nucleotide-sugar donors as metabolic sensors that coordinate two different glycosylation pathways, demonstrating how their interplay is relevant to disease outcome in the most common congenital disorder of glycosylation.
2024-12-27 | GSE269074 | GEO
Project description:SF3B1 mutations frequently occur in cancer yet lack targeted therapies. Clinical trials of XPO1 inhibitors, selinexor and eltanexor, in high-risk myelodysplastic neoplasms (MDS) revealed responders were enriched with SF3B1 mutations. Given that XPO1 (Exportin-1) is a nuclear exporter responsible for the export of proteins and multiple RNA species, this led to the hypothesis that SF3B1-mutant cells are sensitive to XPO1 inhibition, potentially due to altered splicing. Subsequent RNA sequencing after XPO1 inhibition in SF3B1 wildtype and mutant cells showed increased nuclear retention of RNA transcripts and increased alternative splicing in the SF3B1 mutant cells particularly of genes that impact apoptotic pathways. To identify novel drug combinations that synergize with XPO1 inhibition, a forward genetic screen was performed with eltanexor treatment implicating anti-apoptotic targets BCL2 and BCLXL, which were validated by functional testing in vitro and in vivo. These targets were tested in vivo using Sf3b1K700E conditional knock-in mice, which showed that the combination of eltanexor and venetoclax (BCL2 inhibitor) had a preferential sensitivity for SF3B1 mutant cells without excessive toxicity. In this study, we unveil the mechanisms underlying sensitization to XPO1 inhibition in SF3B1-mutant MDS and preclinically rationalize the combination of eltanexor and venetoclax for high-risk MDS.
| S-EPMC11347370 | biostudies-literature