Project description:Tuberculosis (TB) remains a prevalent and lethal infectious disease. The glycobiology associated with Mycobacterium tuberculosis infection of frontline alveolar macrophages is still unresolved. Herein, we investigated the regulation of protein N-glycosylation in human macrophages and their secreted microparticles (MPs) used for intercellular communication upon M. tb infection. LC-MS/MS-based proteomics and glycomics were performed to monitor the regulation of glycosylation enzymes and receptors and the N-glycome in in vitro-differentiated macrophages and in isolated MPs upon M. tb infection. Infection promoted a dramatic regulation of the macrophage proteome. Most notably, significant infection-dependent down-regulation (4-26 fold) of 11 lysosomal exoglycosidases e.g. β-galactosidase, β-hexosaminidases and α-/β-mannosidases was observed. Relative weak infection-driven transcriptional regulation of these exoglycosidases and a stronger augmentation of the extracellular hexosaminidase activity demonstrated that the lysosome-centric changes may originate predominantly from infection-induced secretion of the lysosomal content. The macrophages showed heterogeneous N-glycan profiles and displayed significant up-regulation of complex-type glycosylation and concomitant down-regulation of paucimannosylation upon infection. Complementary intact N-glycopeptide analysis supported a subcellular-specific manipulation of the glycosylation machinery and altered glycosylation patterns of lysosomal N-glycoproteins within infected macrophages. Interestingly, the corresponding macrophage-derived MPs displayed unique N-glycome and proteome signatures supporting a preferential packaging from plasma membranes. The MPs were devoid of infection-dependent N-glycosylation signatures, but interestingly displayed increased levels of the glyco-initiating oligosaccharyltransferase complex and associated α-glucosidases that correlated with increased formation, N-glycan precursor levels and N-glycan density of infected MPs. In conclusion, this system-wide study provides new insight into the host- and pathogen-driven N-glycoproteome manipulation of macrophages in TB.

Project description:Rationale: To identify functionally relevant common genetic risk variants associated with idiopathic pulmonary fibrosis (IPF), we performed expression quantitative trait loci (eQTL) and methylation quantitative trait loci (mQTL) mapping, followed by co-localization of eQTL and mQTL with genetic association signals as well as mediation analysis. Methods: Illumina MEGA genotyping arrays, mRNA sequencing, and Illumina 850k methylation arrays were performed on lung tissue of participants with IPF (234 RNA and 345 DNA samples) and non-diseased control (188 RNA and 202 DNA samples). Transcriptome and methylome datasets were normalized for unknown batch effects using Probabilistic Estimation of Expression Residuals (PEER). eQTL, cell type-interaction eQTL, and mQTL analyses were performed in FastQTL and co-localization analysis in eCAVIAR separately for cases and controls. Benjamini-Hochberg false discovery rate was used for adjustment for multiple comparisons. Results: After appropriate adjustment, we identified 4,745 genes with significant eQTLs in controls and 6,047 in cases (FDR-adjusted p<0.05). Focusing on genetic variants within 10 primary IPF-associated genetic loci, we identified 27 eQTLs in controls and 24 eQTLs in cases (FDR-adjusted p<0.05). Among these signals, we identified association of rs35705950 with expression of MUC5B (Chr11 locus) and rs2076295 with expression of DSP (Chr6 locus) in both cases and controls. To address cell specificity, we performed cell type-interaction eQTL analysis and identified an association of rs2076295 with expression of DSP in smooth muscle cells. mQTL analysis identified CpGs in gene bodies of MUC5B (cg17589883) and DSP (cg08964675) associated with the lead variants in these two loci. eCAVIAR demonstrated strong co-localization of eQTL/mQTL and genetic signal in MUC5B (rs35705950) and DSP (rs2076295) in both cases and controls. Mediation analysis demonstrated partial mediation of the effect of common variants in MUC5B and DSP loci on disease risk though MUC5B and DSP gene expression. Functional validation of the mQTL in MUC5B demonstrates that the CpG is within a putative internal repressor element that interacts through a 3D loop with the enhancer containing the rs35705950 genetic variant. Conclusions: Using lung eQTL/mQTL, co-localization, and mediation analyses, we have established the functional validation of the common IPF genetic risk variants for MUC5B (rs35705950) and DSP (rs2076295). These results provide additional evidence that both MUC5B and DSP are involved in the etiology of IPF.

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RNA-seq of monocyte derived macrophages and dendritic cells in a Peruvian Tuberculosis cohort

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