Project description:To better examine the molecular mechanisms behind the virus infection, we conducted a correlation analysis of RNA-Seq and quantitative iTRAQ-LC-MS/MS in TuMV-infected and in healthy Chinese cabbage leaves.
Project description:Highly specialized cells are fundamental for proper functioning of complex organs. Variations in cell-type specific gene expression and protein composition have been linked to a variety of diseases. Although single cell technologies have emerged as valuable tools to address this cellular heterogeneity, a majority of these workflows lack sufficient in situ resolution for functional classification of cells and are associated with extremely long analysis time, especially when it comes to in situ proteomics. In addition, lack of understanding of single cell dynamics within their native environment limits our ability to explore the altered physiology in disease development. This limitation is particularly relevant in the mammalian brain, where different cell types perform unique functions and exhibit varying sensitivities to insults. The hippocampus, a brain region crucial for learning and memory, is of particular interest due to its obvious involvement in various neurological disorders. Here, we present a combination of experimental and data integration approaches for investigation of cellular heterogeneity and functional disposition within the mouse brain hippocampus using MALDI Imaging mass spectrometry (MALDI-IMS) and shotgun proteomics (LC-MS/MS) coupled with laser-capture microdissection (LCM) along with spatial transcriptomics. Within the dentate gyrus granule cells we identified two proteomically distinct cellular subpopulations that are characterized by a substantial number of discriminative proteins. These cellular clusters contribute to the overall functionality of the dentate gyrus by regulating redox homeostasis, mitochondrial organization, RNA processing, and microtubule organization. Importantly, most of the identified proteins matched their transcripts, verifying the in situ protein identification and supporting their functional analyses. By combining high-throughput spatial proteomics with transcriptomics, our approach enables reliable near-single-cell scale identification of proteins and profiling of inter-cellular heterogeneity within similar cell-types in tissues. This methodology has the potential to be applied to different biological conditions and tissues, providing a deeper understanding of cellular subpopulations in situ.
Project description:Quantitative protein extraction from biological samples, as well as contaminants removal before LC-MS/MS, is fundamental for the successful bottom-up proteomic analysis. Four sample preparation methods, including the filter-aided sample preparation (FASP), two single-pot solid-phase-enhanced sample preparations (SP3) on carboxylated or HILIC paramagnetic beads, and protein suspension trapping method (S-Trap) were evaluated for SDS removal and protein digestion from Arabidopsis thaliana (AT) lysate. Finally, the optimized carboxylated SP3 workflow was benchmarked closely against the routine FASP. Ultimately, LC-MS/MS analyses revealed that regarding the number of identifications, number of missed cleavages, proteome coverage, repeatability, reduction of handling time, and cost per assay, the SP3 on carboxylated magnetic particles proved to be the best alternative for SDS and other contaminants removal from plant sample lysate. A robust and efficient 2-h SP3 protocol for a wide range of protein input is presented, benefiting from no need to adjust the amount of beads, binding and rinsing conditions, or digestion parameters.
Project description:We did LC-MS untargeted lipidomics of primary human fibroblasts to have a comprehensive overview of their lipidome in positive ion mode
Project description:A high-resolution/accurate-mass DNA adductomic approach was developed to investigate anticipated and unknown DNA adducts induced by DNA alkylating agents in biological samples. Two new features were added to a previously developed approach to significantly broaden its scope, versatility, and selectivity. First, the neutral loss of a base (guanine, adenine, thymine, or cytosine) was added to the original methodology's neutral loss of the 2'-deoxyribose moiety to allow for the detection of all DNA base adducts. Second, targeted detection of anticipated DNA adducts based on the reactivity of the DNA alkylating agent was demonstrated by inclusion of an ion mass list for data dependent triggering of MS(2) fragmentation events and subsequent MS(3) fragmentation. Additionally, untargeted screening of the samples, based on triggering of an MS(2) fragmentation event for the most intense ions of the full scan, was included for detecting unknown DNA adducts. The approach was tested by screening for DNA mono and cross-linked adducts in purified DNA and in DNA extracted from cells treated with PR104A, an experimental DNA alkylating nitrogen mustard prodrug currently under investigation for the treatment of leukemia. The results revealed the ability of this new DNA adductomic approach to detect anticipated and unknown PR104A-induced mono and cross-linked DNA adducts in biological samples. This methodology is expected to be a powerful tool for screening for DNA adducts induced by endogenous or exogenous exposures.
Project description:The anterior silk gland in the silkworm plays an important role in the process of liquid fibroin to solid silk fiber .In view of this,the proteomics analysis was applied to to study the relationship between the function of proteins in the anterior silk gland and the mechanism of spinning. The anterior silk glands on the 3rd day of fifth instar were dissected.Aftter 1D SDS-PAGE ,one gel lane was cut into 10 bands and each band further sliced into small pieces was subjected to in-gel tryptic digestion for 20 hours.The digested peptides were separated by RP nanoscale capillary liquid chromatography and analyzed using a surveyor LC system (Thermo Figgigan, San Jose, CA).The eluate from the RP column was analyzed by Finnigan LTQ(Thermo Electron Corporation)linear ion trap Mass equipped with a nanospray souce in the positive ion mode. The MS analysis was performed with one full MS scan followed by three MS/MS scans on the most intense ions from the MS spectrum with the dynamic exclusion settings: repeat count 2, repeat duration 30s, exclusion duration 90s. Data were acquired in data-dependent mode using Xcalibur software.Ten raw datasets from LC-MS/MS were searched against the predicted silkworm database by Xia.et al which consists of 21312 silkworm proteins.The searching was carried out with the Turbo SEQUEST(Bioworks version 3.2, Thermo Electron).
Project description:We developed a general method to detect cellular small molecule-RNA conjugates that does not rely on the reactivity of the small molecule. This technique revealed NAD-linked RNA in Escherichia coli and Streptomyces venezuelae. Subsequent characterization showed that NAD is a 5' modification of RNA, cannot be installed in vitro through aberrant transcriptional initiation, is only found among smaller cellular RNAs and is present at a surprisingly high abundance of approximately 3,000 copies per cell.
Project description:Short chain fatty acids were shown to affect regulatory immune response in context of autoimmune diseases like multiple sclerosis (MS). Recent studys in an animal model of MS revealed significant impact of short chain fatty acid propionate (PA) on the differentiation towards regulatory Tcells (Treg). In a translational proof of concept study PA was administered to relapse remitting MS patients. We observed an increase of Treg in peripheral blood as well as functional improvement in Treg suppressive capacity beside a decrease of proinflammatory Thelper1 and 17 cells. To investigate underlying mechanisms of the observed shift in immune cell balance, intensive transcriptomic analysis on isolated Treg from whole blood PBMC of PA treated relapse remitting MS patients was performed at baseline, 14 days and 90 days of treatment.