De novo Fatty Acid Biosynthesis Contributes Significantly to Establishment of a Bioenergetically Favorable Environment for Vaccinia Virus Infection
| Autor: | Paula Traktman, Matthew D. Greseth |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Palmitates
Poxviridae Infections Protein Synthesis Mitochondrion Biochemistry Energy-Producing Processes Viral Packaging chemistry.chemical_compound Chlorocebus aethiops Molecular Cell Biology Protein palmitoylation lcsh:QH301-705.5 Energy-Producing Organelles Protein Metabolism biology Fatty Acids Oxygen Metabolism Cellular Structures Electrophoresis Gel Pulsed-Field Enzymes Nucleic acids Fatty acid synthase Virion assembly Metabolic Pathways Research Article lcsh:Immunologic diseases. Allergy Immunology Vaccinia virus Bioenergetics DNA replication Biosynthesis Microbiology Cell Line Host-Parasite Interactions Microscopy Electron Transmission Virology Genetics Animals Viroplasm Biology Molecular Biology Virus Assembly Virion Proteins DNA Lipid Metabolism Viral Replication Cerulenin Citric acid cycle Metabolism Microscopy Fluorescence Subcellular Organelles lcsh:Biology (General) chemistry biology.protein Parasitology lcsh:RC581-607 Etomoxir |
| Zdroj: | PLoS Pathogens PLoS Pathogens, Vol 10, Iss 3, p e1004021 (2014) |
| ISSN: | 1553-7374 |
| DOI: | 10.1371/journal.ppat.1004021 |
| Popis: | The poxvirus life cycle, although physically autonomous from the host nucleus, is nevertheless dependent upon cellular functions. A requirement for de novo fatty acid biosynthesis was implied by our previous demonstration that cerulenin, a fatty acid synthase inhibitor, impaired vaccinia virus production. Here we show that additional inhibitors of this pathway, TOFA and C75, reduce viral yield significantly, with partial rescue provided by exogenous palmitate, the pathway's end-product. Palmitate's major role during infection is not for phospholipid synthesis or protein palmitoylation. Instead, the mitochondrial import and β-oxidation of palmitate are essential, as shown by the impact of etomoxir and trimetazidine, which target these two processes respectively. Moreover, the impact of these inhibitors is exacerbated in the absence of exogenous glucose, which is otherwise dispensable for infection. In contrast to glucose, glutamine is essential for productive viral infection, providing intermediates that sustain the TCA cycle (anaplerosis). Cumulatively, these data suggest that productive infection requires the mitochondrial β-oxidation of palmitate which drives the TCA cycle and energy production. Additionally, infection causes a significant rise in the cellular oxygen consumption rate (ATP synthesis) that is ablated by etomoxir. The biochemical progression of the vaccinia life cycle is not impaired in the presence of TOFA, C75, or etomoxir, although the levels of viral DNA and proteins synthesized are somewhat diminished. However, by reversibly arresting infections at the onset of morphogenesis, and then monitoring virus production after release of the block, we determined that virion assembly is highly sensitive to TOFA and C75. Electron microscopic analysis of cells released into C75 revealed fragmented aggregates of viroplasm which failed to be enclosed by developing virion membranes. Taken together, these data indicate that vaccinia infection, and in particular virion assembly, relies on the synthesis and mitochondrial import of fatty acids, where their β-oxidation drives robust ATP production. Author Summary Vaccinia virus, the prototypic poxvirus, is closely related to variola virus, the etiological agent of smallpox. A full understanding of the poxviral life cycle is imperative for the development of novel antiviral therapies, the design of new vaccines, and the effective and safe use of these viruses as oncolytic agents. Metabolomic studies have shed light on the novel mechanisms used by viruses to replicate efficiently within their hosts. de novo fatty acid biosynthesis has been shown to be of relevance for numerous viral infections as well as for the development of cancer. Here we describe an important role for de novo fatty acid biosynthesis during vaccinia infection. Ongoing synthesis of palmitate is needed to fuel the production of energy within mitochondria. The biochemical events of viral DNA replication and protein synthesis are minimally affected by inhibition of this pathway, but viral assembly is disrupted more dramatically. Further exploration of this pathway will provide additional insight into the infectious cycle and inform new therapeutic strategies for this important class of pathogen. |
| Databáze: | OpenAIRE |
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