CANCELLED: March 2020 Meeting

Speaker: Carlos Larriba-Andaluz, Purdue School of Engineering & Technology

Topic: Understanding Ion Mobility Separation in High-Resolution Instruments. Caveats of and deviations from the Mason-Schamp Equation for small molecules.

Look for this talk to be re-scheduled in the future!

February 2020 Meeting

Speaker: Casey Daniels, NIH NIAID

Topic: The dynamic ADP-ribosylome, phosphoproteome, and interactome in LPS-activated macrophages

Date: Monday, February 10th, 2020

Time: 6:15 pm Dinner, 7:15 pm Presentation

Location: Shimadzu Scientific Instruments, Inc. Training Center 7100 Riverwood Drive, Columbia, MD 21046 (Directions)

Dinner: Please RSVP to Meghan Burke (meghan.burke@nist.gov) by Friday, February 7th if you will be attending the dinner.

Abstract: The innate immune response relies on efficient, robust, and controlled protein signaling networks to relay information related to pathogen or viral detection. This communication is mediated primarily through protein-protein interactions and post-translational modifications (PTMs), events which are best characterized by mass spectrometry (MS)-based proteomics. This in-depth study uses MS to identify changes in protein signaling networks of lipopolysaccharide (LPS)-stimulated human and mouse macrophages, at the level of single PTMs and protein complexes. Protein ADP-ribosylation is truncated down to its phosphoribose attachment structure, allowing for enrichment of the resulting phosphoribosylated peptides along with co-occurring phoshopeptides by immobilized metal affinity chromatography. Additionally, size exclusion chromatography-MS (SEC-MS) is used to separate protein complexes and proteoforms based on size; known and novel protein complexes are then identified by weighted correlation network analysis (WGCNA) – a machine learning algorithm for unsupervised clustering into modules – based on their correlated movement into or out of SEC fractions following LPS stimulation. It is only after unsupervised clustering has been performed that established databases are used to characterize the protein modules, which prove to be highly interactive based on known protein-protein interactions, and of similar biological processes, molecular functions, and/or cellular compartments based on gene ontology. Two modules of interest – one linked to the ASK complex, the other containing PARP9 as a hub protein – are studied further through immunoprecipitation and PTM analysis. Finally, PARP inhibition is used to perturb the characterized systems, demonstrating the importance of protein ADP-ribosylation for the global protein interactome. All PTM and interactome data has been aggregated into a meta-database of 6,729 proteins, with ADP-ribosylation characterized on 2,905 proteins, and phosphorylation characterized on 2,669 proteins; expanding the number of proteins with endogenous ADP-ribosylation sites characterized, identifying ADP-ribosylation in primary human cells for the first time, and surveying protein phosphorylation in human macrophages for the first time. This database serves as an invaluable resource for studying crosstalk between the ADP-ribosylome, phosphoproteome, and interactome.

January 2020 Meeting

Speaker: Alison Scott, University of Maryland

Topic: Exploring the spatially-resolved lipidome during lung infection by Gram-negative pathogens using mass spectrometry imaging

Date: Monday, January 13th, 2020

Time: 6:15 pm Dinner, 7:15 pm Presentation

Location: Shimadzu Scientific Instruments, Inc. Training Center 7100 Riverwood Drive, Columbia, MD 21046 (Directions)

Dinner: Please RSVP to Meghan Burke (meghan.burke@nist.gov) by Friday, January 10th if you will be attending the dinner.

Abstract: Mass spectrometry imaging (MSI) is a technique for mapping the spatial distributions of molecules in sectioned tissue. Histology-preserving tissue preparation methods are central to successful MSI studies. Common fixation methods, used to preserve tissue morphology, can result in artifacts in the resulting MSI experiment including delocalization of analytes, altered adduct profiles, and loss of key analytes due to irreversible cross-linking and diffusion. This is especially troublesome in lung and airway samples, in which histology and morphology is best interpreted from 3D reconstruction, requiring the large and small airways to remain inflated during analysis. We developed an MSI-compatible inflation containing as few exogenous components as possible, forgoing perfusion, fixation, and addition of salt solutions upon inflation that resulted in an ungapped 3D molecular reconstruction through more than 300 microns. We characterized a series of polyunsaturated phospholipids (PUFA-PLs), specifically phosphatidylinositol (-PI) lipids linked to lethal inflammation in bacterial infection and mapped them in serial sections of inflated mouse lung. PUFA-PIs were identified using spatial lipidomics and determined to be spatially determinant markers of major airway features using unsupervised hierarchical clustering. Using this preparation in combination with high-content lipidome imaging, we characterized the dynamic response of the same host lipids in the context of infection by Gram-negative pathogens in mouse lungs. Two infection models were used (Francisella novicida and Pseudomonas aeruginosa) to illustrate the divergent innate immune lipid response from Toll-like receptor 4 (TLR4)-silent and TLR4-stimulating pathogens, respectively. Network analysis of the lipid response was indicative of a neutrophil-driven response to TLR4-stimulating infection. In combination, the lung inflation method and infection modeling facilitate a new portal to understand the complex role of host lipid remodeling in the innate immune response.

December 2019 Meeting

Speaker: Asher Newsome, Smithsonian Institution

Topic: Ambient Sampling and Ionization for Mass Spectrometry of Museum Objects
and Materials

Date: Monday, December 16th, 2019

Time: 6:15 pm Dinner, 7:15 pm Presentation

Location: Shimadzu Scientific Instruments, Inc. Training Center 7100 Riverwood Drive, Columbia, MD 21046 (Directions)

Dinner: Please RSVP to Meghan Burke (meghan.burke@nist.gov) by Friday, December 13th if you will be attending the dinner.

Abstract: The pace of development of ambient mass spectrometry has hardly slowed since kicking off fifteen years ago. Whether a given technique moves from academia to industry or follows some other path, often a design originally intended to be a general-purpose analytical MS tool – versatile, based on fundamental principles, relatively open-source – becomes increasingly engineered toward niche applications, particularly the biomedical and defense markets. With some 150 million objects (including living specimens) in its collection that have been selected for conservation and are available for study, the interests of the Smithsonian Institution fill every niche. The versatility, modularity, and throughput of our mass spectrometry systems are therefore a top priority. A varied selection of our recent projects using ambient ionization, direct analysis in real time (DART), and solid phase microextraction (SPME) to analyze ancient, historic, and modern objects is presented, as well as some of our instrumental modifications to accommodate the unique needs of a museum.

November 2019 Meeting

Speaker: Xiaoyu Yang, National Institute of Standards and Technology

Topic: Searching a Comprehensive High Resolution Tandem Mass Spectral Library for Accurate Metabolite Identification

Date: Monday, November 18th, 2019

Time: 6:15 pm Dinner, 7:15 pm Presentation

Location: Shimadzu Scientific Instruments, Inc. Training Center 7100 Riverwood Drive, Columbia, MD 21046 (Directions)

Dinner: Please RSVP to Meghan Burke (meghan.burke@nist.gov) by Friday, November 15th if you will be attending the dinner.

Abstract: Identifying metabolites from millions of electrospray-generated tandem mass spectra is highly challenging, especially in view of the complex chemistry occurring in the electrospray process. We are working to assist in the identification process through the development of a comprehensive reference tandem mass spectral library. We will describe our two part approach. First, we are rapidly building a fully annotated library of all major ions generated in the electrospray process for compounds of analytical interest. Second, we are extending search algorithms to identify compounds not present in the library, but which have similar fragmentation mechanisms. We will describe our latest developments in these areas, with a focus on human metabolite identification.