title: Changes in the Proteome of Langat-Infected Ixodes scapularis ISE6 Cells: Metabolic Pathways Associated with Flavivirus Infection.
abstract: BACKGROUND
  Ticks (Family Ixodidae) transmit a variety of disease causing agents to humans and animals. The tick-borne flaviviruses (TBFs; family Flaviviridae) are a complex of viruses, many of which cause encephalitis and hemorrhagic fever, and represent global threats to human health and biosecurity. Pathogenesis has been well studied in human and animal disease models. Equivalent analyses of tick-flavivirus interactions are limited and represent an area of study that could reveal novel approaches for TBF control.
  
  
  RESULTS
  High resolution LC-MS/MS was used to analyze the proteome of Ixodes scapularis (Lyme disease tick) embryonic ISE6 cells following infection with Langat virus (LGTV) and identify proteins associated with viral infection and replication. Maximal LGTV infection of cells and determination of peak release of infectious virus, was observed at 36 hours post infection (hpi). Proteins were extracted from ISE6 cells treated with LGTV and non-infectious (UV inactivated) LGTV at 36 hpi and analyzed by mass spectrometry. The Omics Discovery Pipeline (ODP) identified thousands of MS peaks. Protein homology searches against the I. scapularis IscaW1 genome assembly identified a total of 486 proteins that were subsequently assigned to putative functional pathways using searches against the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. 266 proteins were differentially expressed following LGTV infection relative to non-infected (mock) cells. Of these, 68 proteins exhibited increased expression and 198 proteins had decreased expression. The majority of the former were classified in the KEGG pathways: "translation", "amino acid metabolism", and "protein folding/sorting/degradation". Finally, Trichostatin A and Oligomycin A increased and decreased LGTV replication in vitro in ISE6 cells, respectively.
  
  
  CONCLUSIONS
  Proteomic analyses revealed ISE6 proteins that were differentially expressed at the peak of LGTV replication. Proteins with increased expression following infection were associated with cellular metabolic pathways and glutaminolysis. In vitro assays using small molecules implicate malate dehydrogenase (MDH2), the citrate cycle, cellular acetylation, and electron transport chain processes in viral replication. Proteins were identified that may be required for TBF infection of ISE6 cells. These proteins are candidates for functional studies and targets for the development of transmission-blocking vaccines and drugs.
authors: Department of Entomology, College of Agriculture, Purdue University, West Lafayette, Indiana, United States of America.|Markey Center for Structural Biology, Department of Biological Sciences, College of Science, Purdue University, West Lafayette, Indiana, United States of America.
authors: Jeffrey M
authors: JM
authors: Grabowski
authors: Markey Center for Structural Biology, Department of Biological Sciences, College of Science, Purdue University, West Lafayette, Indiana, United States of America.
authors: Rushika
authors: R
authors: Perera
authors: Bindley Bioscience Center, Purdue University, West Lafayette, Indiana, United States of America.
authors: Ali M
authors: AM
authors: Roumani
authors: Bindley Bioscience Center, Purdue University, West Lafayette, Indiana, United States of America.
authors: Victoria E
authors: VE
authors: Hedrick
authors: Bindley Bioscience Center, Purdue University, West Lafayette, Indiana, United States of America.
authors: Halina D
authors: HD
authors: Inerowicz
authors: Department of Entomology, College of Agriculture, Purdue University, West Lafayette, Indiana, United States of America.
authors: Catherine A
authors: CA
authors: Hill
authors: Markey Center for Structural Biology, Department of Biological Sciences, College of Science, Purdue University, West Lafayette, Indiana, United States of America.|Bindley Bioscience Center, Purdue University, West Lafayette, Indiana, United States of America.
authors: Richard J
authors: RJ
authors: Kuhn
mesh_terms: D000818:Animals; D060829:Arthropod Proteins / Q000032:analysis*; D002478:Cells, Cultured; D002853:Chromatography, Liquid; D004669:Encephalitis Viruses, Tick-Borne / Q000254:growth & development*; D054884:Host-Pathogen Interactions; D018884:Ixodes / Q000821:virology*; D053858:Metabolic Networks and Pathways; D020543:Proteome / Q000032:analysis*; D053719:Tandem Mass Spectrometry
chemical_list: D060829:Arthropod Proteins; D020543:Proteome