title: Replication of the Shrimp Virus WSSV Depends on Glutamate-Driven Anaplerosis.
abstract: Infection with the white spot syndrome virus (WSSV) induces a metabolic shift in shrimp that resembles the "Warburg effect" in mammalian cells. This effect is triggered via activation of the PI3K-Akt-mTOR pathway, and it is usually accompanied by the activation of other metabolic pathways that provide energy and direct the flow of carbon and nitrogen. Here we show that unlike the glutamine metabolism (glutaminolysis) seen in most cancer cells to double deaminate glutamine to produce glutamate and the TCA cycle intermediate α-ketoglutarate (α-KG), at the WSSV genome replication stage (12 hpi), although glutaminase (GLS) expression was upregulated, only glutamate was taken up by the hemocytes of WSSV-infected shrimp. At the same time, we observed an increase in the activity of the two enzymes that convert glutamate to α-KG, glutamate dehydrogenase (GDH) and aspartate aminotransferase (ASAT). α-ketoglutarate concentration was also increased. A series of inhibition experiments suggested that the up-regulation of GDH is regulated by mTORC2, and that the PI3K-mTORC1 pathway is not involved. Suppression of GDH and ASAT by dsRNA silencing showed that both of these enzymes are important for WSSV replication. In GDH-silenced shrimp, direct replenishment of α-KG rescued both ATP production and WSSV replication. From these results, we propose a model of glutamate-driven anaplerosis that fuels the TCA cycle via α-KG and ultimately supports WSSV replication.
authors.affiliation: Institute of Biotechnology, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Chun-Yuan
authors.initials: CY
authors.lastname: Li
authors.affiliation: Institute of Biotechnology, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Yi-Jan
authors.initials: YJ
authors.lastname: Wang
authors.affiliation: Department of Life Science, College of Life Science, National Taiwan University, Taipei, Taiwan.
authors.forename: Shiao-Wei
authors.initials: SW
authors.lastname: Huang
authors.affiliation: Institute of Biotechnology, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Cheng-Shun
authors.initials: CS
authors.lastname: Cheng
authors.affiliation: Institute of Biotechnology, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Han-Ching
authors.initials: HC
authors.lastname: Wang
mesh_terms: D000818:Animals; D001219:Aspartate Aminotransferases / Q000378:metabolism; D002867:Chromones / Q000737:chemistry; D002952:Citric Acid Cycle; D018628:Gene Dosage; D016679:Genome, Viral; D005969:Glutamate Dehydrogenase / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism*; D005972:Glutaminase / Q000378:metabolism*; D005973:Glutamine / Q000378:metabolism; D006434:Hemocytes / Q000166:cytology / Q000378:metabolism* / Q000821:virology*; D006458:Hemolymph; D007656:Ketoglutaric Acids / Q000378:metabolism; D055432:Metabolomics; D009025:Morpholines / Q000737:chemistry; D033561:Penaeidae / Q000821:virology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D020123:Sirolimus / Q000737:chemistry; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D014779:Virus Replication; D046848:White spot syndrome virus 1 / Q000502:physiology*
chemical_list: D001219:Aspartate Aminotransferases; D002867:Chromones; D005969:Glutamate Dehydrogenase; D018698:Glutamic Acid; D005972:Glutaminase; D005973:Glutamine; D007656:Ketoglutaric Acids; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D012330:RNA, Double-Stranded; D012333:RNA, Messenger; D020123:Sirolimus; D058570:TOR Serine-Threonine Kinases; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one