May 2020 Virtual Meeting

Speaker: Ira Lurie, George Washington University

Topic: Is GC-MS still the gold standard for the analysis of seized drugs?

Date: Thursday, May 21st, 2020

NEW TIME: 1:00 pm Presentation

Location: Webinar – see emails on May 12 and 19 for invite link. Join the mailing list

Abstract: Gas chromatography electron impact mass spectrometry (GC-EI MS) has been considered the gold standard for the analysis of seized drugs. This technique which combines a high resolution separation step with a highly selective detection technique is well established for commonly encountered illicit drugs such as cocaine and heroin. Most recently there has been an up surge of the so called designer drugs, structural or functional analogs of controlled substances that have been synthesized to mimic the pharmacological effects of the original drug, therefore avoiding classification as illegal and/or detection in standard drug tests. The analysis of these emerging drugs is complicated using GC-EI MS by the high number of analogues present in a given class, for which there exists structurally very similar compounds, such as positional isomers and stereoisomers. Problems encountered during analysis include co-elution, poor chromatographic performance, lack of molecular or diagnostic ions, indistinguishable mass spectra, and solute thermal instability. In this seminar alternative liquid phase techniques will be presented including ultra high performance liquid chromatography (UHPLC) with time of flight (TOF) MS detection, high performance supercritical fluid chromatography (UHPSFC) with MS and UV detection, and multi-dimensional UHPLC with UV and MS detection. In regard to gas phase analysis, the use of cold EI-MS and vacuum ultraviolet (VUV) detection will be explored including the use of a tandem GC-VUV-MS instrument. Emerging drug classes investigated include synthetic cannabinoids, synthetic cathinones, fentanyl analogues and phenethylamine analogues.

April 2020 Virtual Meeting

Speaker: Ben Neely, NIST

Topic: Sea lions and bats and humans, oh my! How to explore mammalian serum proteomes

Date: Monday, April 20th, 2020

NEW TIME: 1:00 pm Presentation

Location: Webinar – see email on April 16 for invite link. Join the mailing list

Abstract: Comparative biology and biomimicry are broadly focused on understanding the underlying molecular basis of phenotypes relevant to chronic human ailments. Notably, research in hibernating mammals is improving our understanding of neurodegeneration, studies of diving mammals is identifying novel mechanisms of ischemia/reperfusion injury resistance, while studying organisms that follow Peto’s paradox is advancing longevity and cancer research. In addition to biomimetics, recent events are highlighting certain mammal’s ability to serve as reservoirs of infectious disease. Systematically characterizing the diversity of all mammalian proteomes will enable unexpected discoveries, but this presents numerous technological hurdles. In this seminar I will present results, recommendations and solutions to the issues of working in species without genomes or annotations, acquiring proteomic data in a standardized fashion, comparing proteomes between species and identifying molecular trends across clades with relevant phenotypes. Using the Atlantic bottlenose dolphin and California sea lion as examples, I will demonstrate improvements in proteomic analysis using genomic sequencing and gene annotation techniques, as well as emerging proteomic techniques such as data-independent acquisition applied to undepleted human and bat serum.

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.