Project description:Mycobacterium abscessus is nowadays under the spotlight of the scientific community. This pathogenic mycobacteria is indeed responsible for a wide spectrum of infections involving mostly pulmonary infections in patients with cystic fibrosis. M. abscessus is intrinsically resistant to a broad range of antibiotics, including most antitubercular drugs, and is considered the most pathogenic and chemotherapy-resistant rapidly growing mycobacterium. Consequently, with very limited treatment options, the development of new therapeutic approaches to fight this pathogen are urgently needed. In this context, 19 oxadiazolone (OX) derivatives have been investigated for their antibacterial activity against both the rough (R) and smooth (S) variants of M. abscessus. Several OXs were active against extracellular M. abscessus growth with moderated minimal inhibitory concentrations (MIC), or intracellularly by inhibiting M. abscessus growth inside infected macrophages with MIC values similar to those of imipenem. Such promising results prompted us to identify the potential target enzymes of the sole extra and intracellular inhibitor of M. abscessus growth, i.e., iBpPPOX via activity-based protein profiling combined with mass spectrometry. This approach led to the identification of 21 potential protein candidates being mostly involved in M. abscessus lipid metabolism and/or in cell wall biosynthesis.
Project description:Mycobacterium abscessus is nowadays under the spotlight of the scientific community. This pathogenic mycobacteria is indeed responsible for a wide spectrum of infections involving mostly pulmonary infections in patients with cystic fibrosis. M. abscessus is intrinsically resistant to a broad range of antibiotics, including most antitubercular drugs, and is considered the most pathogenic and chemotherapy-resistant rapidly growing mycobacterium. Consequently, with very limited treatment options, the development of new therapeutic approaches to fight this pathogen are urgently needed. 38 new analogs of Cyclipostins & Cyclophostin (CyC), compounds naturally produced by Streptomyces species, have been synthesized. Their antibacterial activities against clinical isolates belonging to the M. chelonae-abscessus clade, as well as Gram-negative and Gram-positive bacteria have been evaluated by the REMA method. The intracellular activities of the CyC against intramacrophagic M. abscessus have also been investigated and compared to those of imipenem. The CyCs displayed very low toxicity towards host cells and their inhibitory activity was exclusively restricted to mycobacteria. The best candidate, CyC17, showed a high selectivity for mycobacteria with MIC values (<2 up to 40 µg/mL) comparable to those of most classical antibiotics used to treat M. abscessus infections. Of importance, several CyCs were active against extracellular M. abscessus growth (i.e., CyC17 / CyC18β / CyC25 / CyC26) or against intracellular mycobacteria inside macrophages (i.e., CyC7α,β / CyC8α,β) with MIC values similar to or better than those of standard antibiotics. Based on these results, we intended to identify the potential target enzymes of CyC17/CyC26 in M. abscessus by activity-based protein profiling (ABPP) approach coupled with mass spectrometry differential analysis.
Project description:To identify NLRP6-associated proteins in living cells, we applied an APEX2-based labelling method combined with mass spectrometry. In brief, APEX2 was genetically fused to NLRP6. In the presence of hydrogen peroxide, APEX2 catalysed biotin-phenol to become a biotin-phenol radical that covalently bound to NLRP6 neighbouring proteins (<20 nm). The biotinylated proteins were enriched and collected by streptavidin beads. One-dimensional SDS–PAGE followed by liquid chromatography-tandem mass spectrometry (GeLC–MS/MS) was performed to identify the proteins. To detect ubiquitinated p85α, a Flag-tagged p85α plasmid was transfected into cells. The cell lysates were immunoprecipitated with anti-Flag and separated on a 6% SDS–PAGE gel. After in-gel digestion, the resulting peptides were extracted for GeLC–MS/MS analysis.
Project description:Deubiquitinases (DUBs), frequently overactivated in cancers, are associated with tumorigenesis and regarded as promising therapeutic targets. However, the underlying mechanism of DUBs promoting non-small cell lung cancer (NSCLC) are poorly understood. Through a global analysis of the contribution of 97 DUBs in NSCLC survival possibilities by The Cancer Genome Atlas (TCGA) database, we found that high expression of Josephin Domain-containing protein 2 (JOSD2) predicted the poor prognosis of patients. Depletion of JOSD2 significantly impeded NSCLC growth in vivo in both cell/patient-derived xenografts. Mechanistically, JOSD2 inhibits LKB1 kinase activity by removing K6-linked polyubiquitination, which was critical for maintaining LKB1-STRAD-MO25 complex integrity. Furthermore, we identified the first small molecule inhibitor of JOSD2 and the pharmacological inhibition of JOSD2 significantly arrested NSCLC proliferation in vitro/in vivo. Notably, our findings demonstrate a crucial role of JOSD2 in hindering LKB1 activity, highlighting JOSD2 as a potential therapeutic target in NSCLC and providing its inhibitors as a promising strategy for NSCLC treatment.
Project description:The N-terminal three zinc finger motifs of PARP1 are evolutionarily conserved in multicellular organism。However, during apoptosis, human PARP1 is mainly cleaved by caspase 3 at D214. As a result, the truncated PARP1 loses two N-terminal zinc finger motifs and only contains the third zinc finger motif, the BRCT domain, the WGR domain and the C-terminal catalytic domain. Interestingly, when we explored the domain architecture of PARP1 in other organisms, we found that similar to human tPARP1, PARP1 orthologs in several lower organisms do not have the N-terminal two zinc fingers or even they lack the third zinc finger motif. It indicates that even without the first two zinc finger motifs, tPARP1 may still catalyze ADP-ribosylation and play an important role in certain biological processes. To reveal the biological function of tPARP1, we performed tandem affinity purification and searched for the possible substrates.
Project description:Mass spectrometry data comparing the plasma membrane proteins of Nek1-WT and Nek1-Kat2J MEFs enriched by Pierce™ Cell Surface Protein Isolation Kit.
Project description:In eukaryotes, trimethylation of lysine 9 on histone H3 (H3K9) is associated with transcriptional silencing of transposable elements (TEs). In drosophila ovaries, this heterochromatic repressive mark is thought to be deposited by SetDB1 on TE genomic loci after the initial recognition of nascent transcripts by PIWI-interacting RNAs (piRNAs) loaded on the Piwi protein. Here, we show that the nucleosome remodeler Mi-2, in complex with its partner MEP-1, forms a subunit that is transiently associated, in a MEP-1 C-terminus-dependent manner, with known Piwi interactors, including a recently reported SUMO ligase Su(var)2-10. Together with the histone deacetylase Rpd3, this module is involved in the piRNA-dependent TE silencing, correlated with H3K9 deacetylation and trimethylation. Therefore. drosophila piRNA-mediated transcriptional silencing involves three epigenetic effectors, a remodeler, Mi-2, an eraser, Rpd3 and a writer, SetDB1, in addition to the Su(var)2-10 SUMO ligase.
Project description:This article describes a mass spectrometry data set generated from osteogenic differentiated bone marrow stromal cells (BMSCs) and adipose tissue derived stromal cells (ASCs) of a 24-year old healthy donor spiked with iRT peptides. Cells have been identified via FACS-Analysis positive for CD90 and CD105 and negative for CD14, CD34, CD45 and CD11b and tri-lineage differentiation. Obtaining a sufficient amount of high-quality tissue is the key limiting factor for establishing a region-specific spectral library. Hence, combining existing spectral libraries for data-independent acquisition analysis (DIA) can overcome this major limitation. Moreover, these data can be used to map region-specific proteins and to model region-specific pathways. Both can improve our understanding of the functioning in greater depth. In addition, these data can also be used to determine the optimal settings for measuring proteins and peptides of interest. To create the specific spectral library, the tissue was first homogenized and then fractionated via different types of SDS gel electrophoresis, resulting in 11 fractions. These fractions were analysed by nanoHPLC-ESI-MS/MS, resulting in 24 data files.
Project description:Wilms tumour karyotypes frequently exhibit recurrent, large-scale chromosomal imbalances, among the most common of which are concurrent loss of 1p and gain of 1q. We have previously identified a novel breakpoint at 1p13 by 1Mb-spaced array CGH, and undertook a fine-tiling oligonucleotide array approach to accurately map the region in four tumours exhibiting rearrangements at this locus. The use of a 10 bpspaced platform revealed that all four tumours in fact harboured different breakpoints, which were mapped to target four distinct genes PHTF1, DCLRE1B, TRIM33 and NRAS. The precise breakpoint interval was confirmed for one case to lie within intron 3 of DCLRE1B by quantitative copy number PCR and RT-PCR. In addition, expression profiling revealed a pattern of down- and up-regulation of genes either side of the breakpoint in all cases. Although it appears that no single gene is the driver of this rearrangement, this study highlights the power of fine-tiling oligonucleotide arrays to delineate breakpoint regions identified by other genome-wide screens. Processed data is provided as one archive per processed data file obtained via clicking on the ftp link. Related experiment E-TABM-164.
Project description:Hypoxia results in the changes in expression of many genes, the majority of which are mediated via the transcriptional activity of the hypoxia inducible factor (HIF) complex. However, other mechanisms of gene regulation by hypoxia are likely and include control of mRNA stability, regulation of mRNA translation and regulation mediated by micrornas. The aim of this study is to identify microRNAs which expression is regulated by hypoxia. We chose the breast cancer line MCF7 for study as we had previously characterised the expression of the components of the HIF system in that cell line and undertaken an extensive study of the gene expression profile in response to hypoxia, a prolyl hydroxylase inhibitor dimethyloxalylglycine and HIF-1a isoform manipulations (Eldvidge. G.P. et al. (2006) JBC, vol. 281, 22, 15215-15226).