title: Quantitative proteomic analysis of the brainstem following lethal sarin exposure.
abstract: The brainstem represents a major tissue area affected by sarin organophosphate poisoning due to its function in respiratory and cardiovascular control. While the acute toxic effects of sarin on brainstem-related responses are relatively unknown, other brain areas e.g., cortex or cerebellum, have been studied more extensively. The study objective was to analyze the guinea pig brainstem toxicology response following sarin (2×LD50) exposure by proteome pathway analysis to gain insight into the complex regulatory mechanisms that lead to impairment of respiratory and cardiovascular control. Guinea pig exposure to sarin resulted in the typical acute behavior/physiology outcomes with death between 15 and 25min. In addition, brain and blood acetylcholinesterase activity was significantly reduced in the presence of sarin to 95%, and 89%, respectively, of control values. Isobaric-tagged (iTRAQ) liquid chromatography tandem mass spectrometry (LC-MS/MS) identified 198 total proteins of which 23% were upregulated, and 18% were downregulated following sarin exposure. Direct gene ontology (GO) analysis revealed a sarin-specific broad-spectrum proteomic profile including glutamate-mediated excitotoxicity, calcium overload, energy depletion responses, and compensatory carbohydrate metabolism, increases in ROS defense, DNA damage and chromatin remodeling, HSP response, targeted protein degradation (ubiquitination) and cell death response. With regards to the sarin-dependent effect on respiration, our study supports the potential interference of sarin with CO2/H(+) sensitive chemoreceptor neurons of the brainstem retrotrapezoid nucleus (RTN) that send excitatory glutamergic projections to the respiratory centers. In conclusion, this study gives insight into the brainstem broad-spectrum proteome following acute sarin exposure and the gained information will assist in the development of novel countermeasures.
authors.affiliation: Henry M. Jackson Foundation for the Advancement of Military Medicine, 2729 R Street, Wright Patterson AFB, Dayton, OH 45433, USA; Molecular Bioeffects Branch, Bioeffects Division, 711 Human Performance Wing, Human Effectiveness Directorate, Air Force Research Laboratory (711 HPW/RHDJ), WPAFB, Dayton, OH 45433, USA. Electronic address: mitchell.meade.1@us.af.mil.
authors.forename: Mitchell L
authors.initials: ML
authors.lastname: Meade
authors.affiliation: Henry M. Jackson Foundation for the Advancement of Military Medicine, 2729 R Street, Wright Patterson AFB, Dayton, OH 45433, USA. Electronic address: drahoffmann1@gmail.com.
authors.forename: Andrea
authors.initials: A
authors.lastname: Hoffmann
authors.affiliation: Henry M. Jackson Foundation for the Advancement of Military Medicine, 2729 R Street, Wright Patterson AFB, Dayton, OH 45433, USA. Electronic address: meghan.makley.ctr@us.af.mil.
authors.forename: Meghan K
authors.initials: MK
authors.lastname: Makley
authors.affiliation: Battelle Biomedical Research Center, 1425 Plain City Georgesville Road, West Jefferson, OH 43162, USA. Electronic address: snidert@battelle.org.
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Snider
authors.affiliation: Molecular Bioeffects Branch, Bioeffects Division, 711 Human Performance Wing, Human Effectiveness Directorate, Air Force Research Laboratory (711 HPW/RHDJ), WPAFB, Dayton, OH 45433, USA. Electronic address: john.schlager@us.af.mil.
authors.forename: John J
authors.initials: JJ
authors.lastname: Schlager
authors.affiliation: Henry M. Jackson Foundation for the Advancement of Military Medicine, 2729 R Street, Wright Patterson AFB, Dayton, OH 45433, USA; BoonShoft School of Medicine, Wright State University, 3640 Col. Glenn Highway, Dayton, OH 45433, USA. Electronic address: jeffery.gearhart.ctr@us.af.mil.
authors.forename: Jeffery M
authors.initials: JM
authors.lastname: Gearhart
mesh_terms: D000110:Acetylcholinesterase / Q000097:blood; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001933:Brain Stem / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002491:Central Nervous System Agents / Q000633:toxicity*; D002800:Cholinesterase Inhibitors / Q000633:toxicity; D042002:Chromatin Assembly and Disassembly / Q000187:drug effects; D004249:DNA Damage / Q000187:drug effects; D027341:Excitatory Amino Acid Transporter 1 / Q000378:metabolism; D005260:Female; D006168:Guinea Pigs; D006360:Heat-Shock Proteins / Q000187:drug effects; D040901:Proteomics; D017382:Reactive Oxygen Species / Q000378:metabolism; D012524:Sarin / Q000633:toxicity*
chemical_list: D002135:Calcium-Binding Proteins; D002491:Central Nervous System Agents; D002800:Cholinesterase Inhibitors; D027341:Excitatory Amino Acid Transporter 1; D006360:Heat-Shock Proteins; D017382:Reactive Oxygen Species; D012524:Sarin; D000110:Acetylcholinesterase
keywords: Brain effect; Cytoscape; Quantitative proteomics; Reactome functional interaction network analysis; Sarin