Project description:We have simulated a carrier proteome effect using a two-proteome quantitative TMTPro 9-plex labeled sample series to evaluate the effects of extreme carrier channels on TIMSTOF quantification.
Project description:Single cell proteomics by mass spectrometry (SCoPE-MS) is a recently introduced method that utilizes isobaric labels to quantify multiplexed single cell proteomes. While this technique has generated great excitement, the technologies underlying SCoPE-MS - isobaric labels and mass spectrometry - comprise technical limitations with the potential to unfavorably impact data quality and biological interpretation. These limitations are due to the carrier proteome, a sample added at 25-500x single cell proteomes to enable peptide identifications. Here, we perform SCoPE-MS experiments with increasing amounts of carrier proteome and evaluate quantitative accuracy as it relates to mass analyzer dynamic range, multiplexing level, and number of ions sampled. We demonstrate that an increase in carrier proteome level requires a concomitant increase in the number of ions sampled to maintain quantitative accuracy – we term this the carrier proteome effect. Based on our findings, we provide guidance on experimental design, data collection, and data analysis to limit the impact of the carrier proteome effect within SCoPE-MS measurements.
Project description:Single cell proteomics by mass spectrometry (SCoPE-MS) is a recently introduced method to quantify multiplexed single cell proteomes. While this technique has generated great excitement, the underlying technologies (isobaric labeling and mass spectrometry) comprise technical limitations with the potential to effect data quality and biological interpretation. These limitations are particularly relevant when a carrier proteome, a sample added at 25-500x single cell proteomes, is used to enable peptide identifications. Here, we perform controlled experiments with increasing carrier proteome amounts and evaluate quantitative accuracy as it relates to mass analyzer dynamic range, multiplexing level, and number of ions sampled. We demonstrate that an increase in carrier proteome level requires a concomitant increase in the number of ions sampled to maintain quantitative accuracy. Lastly, we introduce Single Cell Proteomics Companion a program that enables rapid evaluation of single cell proteomics data and recommends instrument and data analysis parameters for improved data quality.
Project description:We probe the carrier proteome effects in single cell proteomics with mixed species TMTpro-labeled samples. We demonstrate that carrier proteomes, while increasing overall identifications, dictate which proteins are identified. We show that quantitative precision and signal intensity are limited at high carrier levels, hindering the recognition of regulated proteins. Guidelines for optimized mass spectrometry acquisition parameters and best practices for fold-change or protein copy number-based comparisons are provided.
Project description:Streptococcus equi subsp. equi (SEE) is a host-restricted bacterium that causes the common infectious upper respiratory disease known as strangles in horses. Perpetuation of SEE infection appears attributable to inapparent carrier horses because it does not persist long-term in the environment, infect other host mammals or vectors, and result in short-lived immunity. Whether pathogen factors enable SEE to remain in horses without causing clinical signs remains poorly understood. Thus, our objective was to use next-generation sequencing technologies to characterize the transcriptome of isolates of SEE from horses with acute clinical strangles and inapparent carrier horses to assess pathogen-associated changes that might reflect adaptions of SEE to the host contributing to inapparent carriage. RNA sequencing of SEE isolates from Pennsylvania demonstrated no genes that were differentially expressed between acute clinical and inapparent carrier isolates of SEE.
Project description:Loss of the mitochondrial pyruvate carrier promotes stem cell gene expression in AOMDSS colon adenomas, though loss of Apc promotes a more unified pehnotype.
Project description:The aim was to determine the identity of genes regulated at 3 d post-olfactory bulbectomy in the olfactory mucosa of carrier-injected Ccl3-/- mice compared with carrier-injected C57BL/6 mice. Total RNA from the OE was hybridized to Affymetrix microarrays. A number of chemokine-, cytokine-, and growth factor-related genes were significantly regulated in the Ccl3-/- mice, and were restored in CCL3 protein-injected Ccl3-/- mice. The results illustrated that CCL3 played a key role in recruitment of macrophages to the OE and provided insight into the genomic regulation involved in OE remodeling.
Project description:Imaging mass spectrometry (IMS) enables the spatially targeted molecular assessment of biological tissues at cellular resolutions. New developments and technologies are essential for uncovering the molecular drivers of native physiological function and disease. Instrumentation must maximize spatial resolution, throughput, sensitivity, and specificity, because tissue imaging experiments consist of thousands to millions of pixels. Here, we report the development and application of a matrix-assisted laser desorption/ionization (MALDI) trapped ion-mobility spectrometry (TIMS) imaging platform. This prototype MALDI timsTOF instrument is capable of 10 ?m spatial resolutions and 20 pixels/s throughput molecular imaging. The MALDI source utilizes a Bruker SmartBeam 3-D laser system that can generate a square burn pattern of <10 × 10 ?m at the sample surface. General image performance was assessed using murine kidney and brain tissues and demonstrate that high-spatial-resolution imaging data can be generated rapidly with mass measurement errors <5 ppm and ?40?000 resolving power. Initial TIMS-based imaging experiments were performed on whole-body mouse pup tissue demonstrating the separation of closely isobaric [PC(32:0) + Na]+ and [PC(34:3) + H]+ (3 mDa mass difference) in the gas phase. We have shown that the MALDI timsTOF platform can maintain reasonable data acquisition rates (>2 pixels/s) while providing the specificity necessary to differentiate components in complex mixtures of lipid adducts. The combination of high-spatial-resolution and throughput imaging capabilities with high-performance TIMS separations provides a uniquely tunable platform to address many challenges associated with advanced molecular imaging applications.