@phdthesis{Chithelen2022,
  author    = {Chithelen, Janice},
  title     = {Targeting viral and host factors to optimize anti-measles virus therapy},
  doi       = {10.25972/OPUS-29305},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-293059},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2022},
  abstract  = {Measles is an ancient disease with historical records as early as the 9th century. Extensive study as well as advances in scientific knowledge of virology have led to identification of the viral pathogen and subsequent development of an effective vaccine leading to global efforts towards measles elimination. In 2018, around 140,000 deaths were reported due to measles with incomplete vaccine coverage being one of the leading causes of resurgence. Measles is highly contagious and often regarded as a childhood illness. However, measles is associated with a number of complications and persistent infections like subacute sclerosing panencephalitis (SSPE), which have brought into focus the need for specific anti-viral therapies. The aim of this study was to target host and viral factors to optimize anti-measles virus therapy. Our approach was to test a panel of compounds known to inhibit host cell functions or viral factors for their antiviral effect on measles replication. Primary human lymphocytes, persistently infected NT2 cells and post-mitotic neurons were used as in vitro model systems of acute, persistent and neuronal infection respectively to test the inhibitors. Using the inhibitors Ceranib-2 and SKI-II to target the sphingolipid metabolism enzymes acid ceramidase and sphingosine kinase in infected human primary lymphocytes, we observed a decreased protein translational capacity mediated by mTORC1, EIF4E and ribosomal protein S6 phosphorylation that probably contributes to the antiviral effect. In the persistently infected neural NT2 cells and post-mitotic neurons derived from LUHMES cells, we observed effective infection inhibition and viral clearance upon treatment with a small non-nucleoside inhibitor (ERDRP-0519) specifically targeting the Morbillivirus large polymerase. Other inhibitors such as Ribavirin and Favipiravir were less effective. To conclude, 1) we identified a mTOR associated protein translation axis associated with the sphingolipid metabolism, which affects measles virus replication and 2) In vitro persistently infected neuronal and post-mitotic neuron models were successfully used as a rapid method to test antivirals against measles virus.},
  language  = {en}
}
@article{LambourGlenzForneretal.2022,
  author    = {Lambour, Benjamin and Glenz, Ren{\´e} and Forner, Carmen and Krischke, Markus and Mueller, Martin J. and Fekete, Agnes and Waller, Frank},
  title     = {Sphingolipid long-chain base phosphate degradation can be a rate-limiting step in long-chain base homeostasis},
  series = {Frontiers in Plant Science},
  volume    = {13},
  journal   = {Frontiers in Plant Science},
  issn      = {1664-462X},
  doi       = {10.3389/fpls.2022.911073},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-277679},
  year      = {2022},
  abstract  = {Sphingolipid long-chain bases (LCBs) are building blocks for membrane-localized sphingolipids, and are involved in signal transduction pathways in plants. Elevated LCB levels are associated with the induction of programmed cell death and pathogen-derived toxin-induced cell death. Therefore, levels of free LCBs can determine survival of plant cells. To elucidate the contribution of metabolic pathways regulating high LCB levels, we applied the deuterium-labeled LCB D-erythro-sphinganine-d7 (D7-d18:0), the first LCB in sphingolipid biosynthesis, to Arabidopsis leaves and quantified labeled LCBs, LCB phosphates (LCB-Ps), and 14 abundant ceramide (Cer) species over time. We show that LCB D7-d18:0 is rapidly converted into the LCBs d18:0P, t18:0, and t18:0P. Deuterium-labeled ceramides were less abundant, but increased over time, with the highest levels detected for Cer(d18:0/16:0), Cer(d18:0/24:0), Cer(t18:0/16:0), and Cer(t18:0/22:0). A more than 50-fold increase of LCB-P levels after leaf incubation in LCB D7-d18:0 indicated that degradation of LCBs via LCB-Ps is important, and we hypothesized that LCB-P degradation could be a rate-limiting step to reduce high levels of LCBs. To functionally test this hypothesis, we constructed a transgenic line with dihydrosphingosine-1-phosphate lyase 1 (DPL1) under control of an inducible promotor. Higher expression of DPL1 significantly reduced elevated LCB-P and LCB levels induced by Fumonisin B1, and rendered plants more resistant against this fungal toxin. Taken together, we provide quantitative data on the contribution of major enzymatic pathways to reduce high LCB levels, which can trigger cell death. Specifically, we provide functional evidence that DPL1 can be a rate-limiting step in regulating high LCB levels.},
  language  = {en}
}
@article{AvotaBodemChithelenetal.2021,
  author    = {Avota, Elita and Bodem, Jochen and Chithelen, Janice and Mandasari, Putri and Beyersdorf, Niklas and Schneider-Schaulies, J{\"u}rgen},
  title     = {The Manifold Roles of Sphingolipids in Viral Infections},
  series = {Frontiers in Physiology},
  volume    = {12},
  journal   = {Frontiers in Physiology},
  issn      = {1664-042X},
  doi       = {10.3389/fphys.2021.715527},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-246975},
  year      = {2021},
  abstract  = {Sphingolipids are essential components of eukaryotic cells. In this review, we want to exemplarily illustrate what is known about the interactions of sphingolipids with various viruses at different steps of their replication cycles. This includes structural interactions during entry at the plasma membrane or endosomal membranes, early interactions leading to sphingolipid-mediated signal transduction, interactions with internal membranes and lipids during replication, and interactions during virus assembly and budding. Targeted interventions in sphingolipid metabolism - as far as they can be tolerated by cells and organisms - may open novel possibilities to support antiviral therapies. Human immunodeficiency virus type 1 (HIV-1) infections have intensively been studied, but for other viral infections, such as influenza A virus (IAV), measles virus (MV), hepatitis C virus (HCV), dengue virus, Ebola virus, and severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), investigations are still in their beginnings. As many inhibitors of sphingolipid metabolism are already in clinical use against other diseases, repurposing studies for applications in some viral infections appear to be a promising approach.},
  language  = {en}
}