@phdthesis{Mayer2019,
  author    = {Mayer, Rafaela},
  title     = {OxPAPC as an endogenous agonist of TRPA1 channels on nociceptors},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175890},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2019},
  abstract  = {Non-steroidal antiinflammatory drugs are most commonly used for inflammatory and postoperative pain. But they lack effectiveness and specificity, leading to severe side effects, like gastric ulcers, asthma and severe bleeding. Oxidized 1-palmitoyl-2-arachinidonoyl-sn-glycero-3-phosphocholine (OxPAPC) plays an important role in inflammatory pain. PAPC is a common phosphatidylcholine of membranes, which can be oxidized by reactive oxygen species. In preliminary experiments, our group found that local injection of OxPAPC in rat paws induces hyperalgesia. In this study we examined the effect of OxPAPC on transient receptor potential A1 (TRPA1), an ion channel expressed in C-fiber neurons. Furthermore, we investigated if intracellular cysteine residues of TRPA1 were necessary for agonist-channel-interactions and if a subsequent TRPA1 activation could be prevented by OxPAPC scavengers. To answer these questions, we performed calcium imaging using HEK-293 cells stably expressing hTRPA1, or transiently expressing the triple mutant channel hTRPA1-3C and na{\"i}ve DRG neurons. Cells were incubated with the ratiometric, fluorescent dye Fura-2/AM and stimulated with OxPAPC. The change of light emission after excitation with 340 and 380 nm wavelengths allowed conclusions regarding changes of intracellular calcium concentrations after TRPA1 activation. In our investigation we proved evidence that OxPAPC activates TRPA1, which caused a flow of calcium ions into the cytoplasm. The TRPA1-specific channel blocker HC-030031 eliminated this agonist-induced response. TRPA1-3C was not completely sensitive to OxPAPC. The peptide D-4F and the monoclonal antibody E06 neutralized OxPAPC-induced TRPA1 activation. In this work, the importance of OxPAPC as a key mediator of inflammatory pain and as a promising target for drug design is highlighted. Our results indicate that TRPA1 activation by OxPAPC involves cysteine-dependent mechanisms, but there are other, cysteine-independent activation mechanisms as well. Potential pharmaceuticals for the treatment of inflammatory pain are D-4F and E06, whose efficiency has recently been confirmed in the animal model by our research group.},
  subject      = {Schmerzforschung},
  language  = {en}
}
@article{OehlerKistnerMartinetal.2017,
  author    = {Oehler, Beatrice and Kistner, Katrin and Martin, Corinna and Schiller, J{\"u}rgen and Mayer, Rafaela and Mohammadi, Milad and Sauer, Reine-Solange and Filipovic, Milos R. and Nieto, Francisco R. and Kloka, Jan and Pfl{\"u}cke, Diana and Hill, Kerstin and Schaefer, Michael and Malcangio, Marzia and Reeh, Peter W. and Brack, Alexander and Blum, Robert and Rittner, Heike L.},
  title     = {Inflammatory pain control by blocking oxidized phospholipid-mediated TRP channel activation},
  series = {Scientific Reports},
  volume    = {7},
  journal   = {Scientific Reports},
  number    = {5447},
  doi       = {10.1038/s41598-017-05348-3},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158536},
  year      = {2017},
  abstract  = {Phospholipids occurring in cell membranes and lipoproteins are converted into oxidized phospholipids (OxPL) by oxidative stress promoting atherosclerotic plaque formation. Here, OxPL were characterized as novel targets in acute and chronic inflammatory pain. Oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (OxPAPC) and its derivatives were identified in inflamed tissue by mass spectrometry and binding assays. They elicited calcium influx, hyperalgesia and induced pro-nociceptive peptide release. Genetic, pharmacological and mass spectrometric evidence in vivo as well as in vitro confirmed the role of transient receptor potential channels (TRPA1 and TRPV1) as OxPAPC targets. Treatment with the monoclonal antibody E06 or with apolipoprotein A-I mimetic peptide D-4F, capturing OxPAPC in atherosclerosis, prevented inflammatory hyperalgesia, and in vitro TRPA1 activation. Administration of D-4F or E06 to rats profoundly ameliorated mechanical hyperalgesia and inflammation in collagen-induced arthritis. These data reveal a clinically relevant role for OxPAPC in inflammation offering therapy for acute and chronic inflammatory pain treatment by scavenging OxPAPC.},
  language  = {en}
}